Physiological sources of reductant for nitrogen fixation activity in Nostoc sp. strain UCD 7801 in symbiotic association with Anthoceros punctatus.

Pure cultures of the symbiotic cyanobacterium-bryophyte association with Anthoceros punctatus were reconstituted by using Nostoc sp. strain UCD 7801 or its 3-(3,4-dichlorophenol)-1,1-dimethylurea (DCMU)-resistant mutant strain, UCD 218. The cultures were grown under high light intensity with CO2 as...

ver descrição completa

Na minha lista:
Detalhes bibliográficos
Main Authors: Steinberg, N A, Meeks, J C
Formato: Artigo
Idioma:en
Publicado em: 1991
Assuntos:
Research Article
Acesso em linha:https://ncbi.nlm.nih.gov/pmc/articles/PMC209240/
https://ncbi.nlm.nih.gov/pubmed/1938924
Tags: Adicionar Tag
Sem tags, seja o primeiro a adicionar uma tag!
id pubmed-209240
record_format dspace
spelling pubmed-2092402003-12-01 Physiological sources of reductant for nitrogen fixation activity in Nostoc sp. strain UCD 7801 in symbiotic association with Anthoceros punctatus. Steinberg, N A Meeks, J C J Bacteriol Research Article Pure cultures of the symbiotic cyanobacterium-bryophyte association with Anthoceros punctatus were reconstituted by using Nostoc sp. strain UCD 7801 or its 3-(3,4-dichlorophenol)-1,1-dimethylurea (DCMU)-resistant mutant strain, UCD 218. The cultures were grown under high light intensity with CO2 as the sole carbon source and then incubated in the dark to deplete endogenous reductant pools before measurements of nitrogenase activities (acetylene reduction). High rates of light-dependent acetylene reduction were obtained both before starvation in the dark and after recovery from starvation, regardless of which of the two Nostoc strains was reconstituted in the association. Rates of acetylene reduction by symbiotic tissue with the wild-type Nostoc strain decreased 99 and 96% after 28 h of incubation in the dark and after reexposure to light in the presence of 5 microM DCMU, respectively. Supplementation of the medium with glucose restored nitrogenase activity in the dark to a rate that was 64% of the illuminated rate. In the light and in the presence of 5 microM DCMU, acetylene reduction could be restored to 91% of the uninhibited rate by the exogenous presence of various carbohydrates. The rate of acetylene reduction in the presence of DCMU was 34% of the uninhibited rate of tissue in association with the DCMU-resistant strain UCD 218. This result implies that photosynthates produced immediately by the cyanobacterium can supply at least one-third of the reductant required for nitrogenase activity on a short-term basis in the symbiotic association. However, high steady-state rates of nitrogenase activity by symbiotic Nostoc strains appear to depend on endogenous carbohydrate reserves, which are presumably supplied as photosynthate from both A. punctatus tissue and the Nostoc strain. 1991-11 /pmc/articles/PMC209240/ /pubmed/1938924 Text en
institution US National Library of Medicine
collection PubMed Central
language en
format Article
topic Research Article
spellingShingle Research Article
Steinberg, N A
Meeks, J C
Physiological sources of reductant for nitrogen fixation activity in Nostoc sp. strain UCD 7801 in symbiotic association with Anthoceros punctatus.
description Pure cultures of the symbiotic cyanobacterium-bryophyte association with Anthoceros punctatus were reconstituted by using Nostoc sp. strain UCD 7801 or its 3-(3,4-dichlorophenol)-1,1-dimethylurea (DCMU)-resistant mutant strain, UCD 218. The cultures were grown under high light intensity with CO2 as the sole carbon source and then incubated in the dark to deplete endogenous reductant pools before measurements of nitrogenase activities (acetylene reduction). High rates of light-dependent acetylene reduction were obtained both before starvation in the dark and after recovery from starvation, regardless of which of the two Nostoc strains was reconstituted in the association. Rates of acetylene reduction by symbiotic tissue with the wild-type Nostoc strain decreased 99 and 96% after 28 h of incubation in the dark and after reexposure to light in the presence of 5 microM DCMU, respectively. Supplementation of the medium with glucose restored nitrogenase activity in the dark to a rate that was 64% of the illuminated rate. In the light and in the presence of 5 microM DCMU, acetylene reduction could be restored to 91% of the uninhibited rate by the exogenous presence of various carbohydrates. The rate of acetylene reduction in the presence of DCMU was 34% of the uninhibited rate of tissue in association with the DCMU-resistant strain UCD 218. This result implies that photosynthates produced immediately by the cyanobacterium can supply at least one-third of the reductant required for nitrogenase activity on a short-term basis in the symbiotic association. However, high steady-state rates of nitrogenase activity by symbiotic Nostoc strains appear to depend on endogenous carbohydrate reserves, which are presumably supplied as photosynthate from both A. punctatus tissue and the Nostoc strain.
author Steinberg, N A
Meeks, J C
author_facet Steinberg, N A
Meeks, J C
author_sort Steinberg, N A
title Physiological sources of reductant for nitrogen fixation activity in Nostoc sp. strain UCD 7801 in symbiotic association with Anthoceros punctatus.
title_short Physiological sources of reductant for nitrogen fixation activity in Nostoc sp. strain UCD 7801 in symbiotic association with Anthoceros punctatus.
title_full Physiological sources of reductant for nitrogen fixation activity in Nostoc sp. strain UCD 7801 in symbiotic association with Anthoceros punctatus.
title_fullStr Physiological sources of reductant for nitrogen fixation activity in Nostoc sp. strain UCD 7801 in symbiotic association with Anthoceros punctatus.
title_full_unstemmed Physiological sources of reductant for nitrogen fixation activity in Nostoc sp. strain UCD 7801 in symbiotic association with Anthoceros punctatus.
title_sort physiological sources of reductant for nitrogen fixation activity in nostoc sp. strain ucd 7801 in symbiotic association with anthoceros punctatus.
publishDate 1991
url https://ncbi.nlm.nih.gov/pmc/articles/PMC209240/
https://ncbi.nlm.nih.gov/pubmed/1938924
_version_ 1759043824945987584

Registos relacionados