The transcription of the cbb operon in Nitrosomonas europaea

Microbiology ◽  
2004 ◽  
Vol 150 (6) ◽  
pp. 1869-1879 ◽  
Author(s):  
Xueming Wei ◽  
Luis A. Sayavedra-Soto ◽  
Daniel J. Arp
Keyword(s):  
Carbon Source ◽  
Regulatory Protein ◽  
Carbon Assimilation ◽  
Nitrosomonas Europaea ◽  
Gene Organization ◽  
Carbon Limitation ◽  
Type I ◽  
Ribulose Bisphosphate Carboxylase ◽  
External Energy ◽  
Bisphosphate Carboxylase

Nitrosomonas europaea is an aerobic ammonia-oxidizing bacterium that participates in the C and N cycles. N. europaea utilizes CO2 as its predominant carbon source, and is an obligate chemolithotroph, deriving all the reductant required for energy and biosynthesis from the oxidation of ammonia (NH3) to nitrite (). This bacterium fixes carbon via the Calvin–Benson–Bassham (CBB) cycle via a type I ribulose bisphosphate carboxylase/oxygenase (RubisCO). The RubisCO operon is composed of five genes, cbbLSQON. This gene organization is similar to that of the operon for ‘green-like’ type I RubisCOs in other organisms. The cbbR gene encoding the putative regulatory protein for RubisCO transcription was identified upstream of cbbL. This study showed that transcription of cbb genes was upregulated when the carbon source was limited, while amo, hao and other energy-harvesting-related genes were downregulated. N. europaea responds to carbon limitation by prioritizing resources towards key components for carbon assimilation. Unlike the situation for amo genes, NH3 was not required for the transcription of the cbb genes. All five cbb genes were only transcribed when an external energy source was provided. In actively growing cells, mRNAs from the five genes in the RubisCO operon were present at different levels, probably due to premature termination of transcription, rapid mRNA processing and mRNA degradation.

Thioalkalivibrio sulfidiphilus sp. nov., a haloalkaliphilic, sulfur-oxidizing gammaproteobacterium from alkaline habitats

2012 ◽  
Vol 62 (Pt_8) ◽  
pp. 1884-1889 ◽  
Author(s):  
Dimitry Y. Sorokin ◽  
Maria S. Muntyan ◽  
Anzhela N. Panteleeva ◽  
Gerard Muyzer
Keyword(s):  
Soda Lake ◽  
16S Rrna Gene Sequencing ◽  
Salinity Range ◽  
Rrna Gene ◽  
Type I ◽  
Ribulose Bisphosphate Carboxylase ◽  
Bisphosphate Carboxylase ◽  
Content Type ◽  
Link Type ◽  
Sulfur Oxidizing

A moderately salt-tolerant and obligately alkaliphilic, chemolithoautotrophic sulfur-oxidizing bacterium, strain HL-EbGr7T, was isolated from a full-scale bioreactor removing H2S from biogas under oxygen-limited conditions. Another strain, ALJ17, closely related to HL-EbGr7T, was isolated from a Kenyan soda lake. Cells of the isolates were relatively long, slender rods, motile by a polar flagellum. Although both strains were obligately aerobic, micro-oxic conditions were preferred, especially at the beginning of growth. Chemolithoautotrophic growth was observed with sulfide and thiosulfate in a pH range of 8.0–10.5 (optimum at pH 10.0) and a salinity range of 0.2–1.5 M total Na+ (optimum at 0.4 M). The genome sequence of strain HL-EbGr7T demonstrated the presence of genes encoding the reverse Dsr pathway and a truncated Sox pathway for sulfur oxidation and enzymes of the Calvin–Benson cycle of autotrophic CO2 assimilation with ribulose-bisphosphate carboxylase/oxygenase (RuBisCO) type I. The dominant cellular fatty acids were C18 : 1ω7, C16 : 0 and C19 : 0 cyclo. Based on 16S rRNA gene sequencing, the two strains belonged to a single phylotype within the genus Thioalkalivibrio in the Gammaproteobacteria . Despite being related most closely to Thioalkalivibrio denitrificans , the isolates were unable to grow by denitrification. On the basis of phenotypic and phylogenetic analysis, the novel isolates are proposed to represent a novel species, Thioalkalivibrio sulfidiphilus sp. nov., with the type strain HL-EbGr7T ( = NCCB 100376T  = UNIQEM U246T).

Ribulose bisphosphate carboxylase—oxygenase: its role in photosynthesis

1986 ◽  
Vol 313 (1162) ◽  
pp. 305-324 ◽  
Keyword(s):  
Electron Transport ◽  
Carbon Assimilation ◽  
Kinetic Properties ◽  
Ribulose Bisphosphate Carboxylase ◽  
Ribulose Bisphosphate ◽  
Rubp Carboxylase ◽  
Bisphosphate Carboxylase ◽  
Triose Phosphate ◽  
Ribulose Bisphosphate Carboxylase Oxygenase

Synthesis of triose phosphate by the chloroplast requires three substrates: light, CO 2 and orthophosphate (P i ). In the response of the rate of carbon assimilation to the concentration of CO 2 , the kinetic properties of RuBP carboxylase-oxygenase (Rubisco) constitute the main limitation at low CO 2 concentrations, while at higher concentrations of CO 2 the limitation is shifted towards the reactions leading to the regeneration of the substrate, RuBP, driven by electron transport. In these circumstances, light or P i or both, can become limiting. The characteristics of Rubisco that can affect photosynthesis fall under three main headings: (1) amount and kinetic constants; (2) activation state; and (3) regulation of catalysis (including the role of effectors, such as Pt and glycerate 3-phosphate (PGA)). These characteristics are analysed, and the role of changes in activity of the enzyme is discussed in the context of limitation and regulation of the photosynthetic process. Other factors considered are the regeneration of RuBP and its relation to electron transport, P i supply, and photorespiration. The influence that expected increases in atmospheric CO 2 concentration, and/or genetic improvements in the characteristics of the enzyme, may have on the present balance between the partial processes of photosynthesis, is discussed.

Photoinhibition of photophosphorylation, adenosine triphosphate content, and glyceraldehyde-3-phosphate dehydrogenase (NADP+) following high-irradiance desiccation of Selaginella lepidophylla

1992 ◽  
Vol 70 (1) ◽  
pp. 205-211 ◽  
Author(s):  
Jefferson G. Lebkuecher ◽  
William G. Eickmeier
Keyword(s):  
Enzyme Activity ◽  
Adenosine Triphosphate ◽  
Enzyme Activities ◽  
Carbon Assimilation ◽  
Bright Light ◽  
High Irradiance ◽  
Ribulose Bisphosphate Carboxylase ◽  
Bisphosphate Carboxylase ◽  
Selaginella Lepidophylla ◽  
Adenosine Phosphate

Selaginella lepidophylla (Hook, and Grev.) Spring, a poikilohydrous desert pteridophyte, curls dramatically during desiccation. As part of a larger study of potential photoinhibition in this resurrection plant, the hypothesis that stem curling may ameliorate high-irradiance reduction of light-activated enzyme activities, noncyclic photophosphorylation, and adenosine triphosphate content was tested under laboratory conditions. Plants restrained from curling during desiccation at a constant irradiance of 2000 μmol ∙ m−2 ∙ s−1 when rehydrated had significantly decreased glyceraldehyde-3-phosphate dehydrogenase (NADP+) enzyme activity, noncyclic photophosphorylation, and adenosine triphosphate content relative to plants that were allowed to curl naturally under the same conditions. Ribulose bisphosphate carboxylase and malate dehydrogenase enzyme activities were not significantly affected by the restraint treatment. These results demonstrate that stem curling during desiccation limits bright-light damage that could otherwise decrease photophosphorylation capacity, adenosine triphosphate content, and light-activated carbon assimilation enzyme activity when the plants are next wetted. In addition, examination of the adenosine phosphate contents of desiccated, 24-h dark hydrated, and 24-h 500 μmol ∙ m−2 ∙ s−1 irradiance hydrated Selaginella lepidophylla plants revealed that adenosine triphosphate pools were not conserved during desiccation and that during hydration in the light, adenosine triphosphate content increases substantially as a result of both oxidative and photophosphorylation. Key words: Selaginella lepidophylla, photoinhibition, desiccation tolerance, photophosphorylation, adenosine phosphate.

scholarly journals Diel Rhythms in Ribulose-1,5-Bisphosphate Carboxylase/Oxygenase and Glutamine Synthetase Gene Expression in a Natural Population of Marine Picoplanktonic Cyanobacteria (Synechococcusspp.)

1999 ◽  
Vol 65 (8) ◽  
pp. 3651-3659 ◽  
Author(s):  
Michael Wyman
Keyword(s):  
Glutamine Synthetase ◽  
Natural Population ◽  
Nitrogen Assimilation ◽  
Large Subunit ◽  
Natural Populations ◽  
Carbon Assimilation ◽  
Ribulose Bisphosphate Carboxylase ◽  
Temporal Separation ◽  
Bisphosphate Carboxylase ◽  
Carbon And Nitrogen

ABSTRACT Diel periodicity in the expression of key genes involved in carbon and nitrogen assimilation in marine Synechococcus spp. was investigated in a natural population growing in the surface waters of a cyclonic eddy in the northeast Atlantic Ocean.Synechococcus sp. cell concentrations within the upper mixed layer showed a net increase of three- to fourfold during the course of the experiment (13 to 22 July 1991), the population undergoing approximately one synchronous division per day. Consistent with the observed temporal pattern of phycoerythrin (CpeBA) biosynthesis, comparatively little variation was found incpeBA mRNA abundance during either of the diel cycles investigated. In marked contrast, the relative abundance of transcripts originating from the genes encoding the large subunit of ribulose bisphosphate carboxylase/oxygenase (rbcL) and glutamine synthetase (glnA) showed considerable systematic temporal variation and oscillated during the course of each diel cycle in a reciprocal rhythm. Whereas activation of rbcL transcription was clearly not light dependent, expression of glnAappeared sensitive to endogenous changes in the physiological demands for nitrogen that arise as a natural consequence of temporal periodicity in photosynthetic carbon assimilation. The data presented support the hypothesis that a degree of temporal separation may exist between the most active periods of carbon and nitrogen assimilation in natural populations of marine Synecoccoccus spp.

scholarly journals The autotrophic growth of Micrococcus denitrificans on Methanol

1975 ◽  
Vol 150 (3) ◽  
pp. 569-571 ◽  
Author(s):  
R B Cox ◽  
J R Quayle
Keyword(s):  
Specific Activity ◽  
Carbon Assimilation ◽  
High Specific Activity ◽  
Ribulose Bisphosphate Carboxylase ◽  
Autotrophic Growth ◽  
Ribulose Bisphosphate ◽  
Bisphosphate Carboxylase ◽  
Physiological Evidence

Ribulose bisphosphate carboxylase is present at a high specific activity in extracts of methanol-grown Microccus denitrificans. Enzymic and physiological evidence indicates that, during growth on methanol, the ribulose bisphosphate cycle is the route of carbon assimilation.

scholarly journals Four Mutant Alleles Elucidate the Role of the G2 Protein in the Development of C4 and C3 Photosynthesizing Maize Tissues

Genetics ◽  
2001 ◽  
Vol 159 (2) ◽  
pp. 787-797
Author(s):  
Lizzie Cribb ◽  
Lisa N Hall ◽  
Jane A Langdale
Keyword(s):  
Cell Types ◽  
Bundle Sheath ◽  
Primary Role ◽  
Ribulose Bisphosphate Carboxylase ◽  
Sheath Cell ◽  
Mesophyll Cells ◽  
Phenotypic Data ◽  
Bisphosphate Carboxylase ◽  
Bundle Sheath Cell

Abstract Maize leaf blades differentiate dimorphic photosynthetic cell types, the bundle sheath and mesophyll, between which the reactions of C4 photosynthesis are partitioned. Leaf-like organs of maize such as husk leaves, however, develop a C3 pattern of differentiation whereby ribulose bisphosphate carboxylase (RuBPCase) accumulates in all photosynthetic cell types. The Golden2 (G2) gene has previously been shown to play a role in bundle sheath cell differentiation in C4 leaf blades and to play a less well-defined role in C3 maize tissues. To further analyze G2 gene function in maize, four g2 mutations have been characterized. Three of these mutations were induced by the transposable element Spm. In g2-bsd1-m1 and g2-bsd1-s1, the element is inserted in the second intron and in g2-pg14 the element is inserted in the promoter. In the fourth case, g2-R, four amino acid changes and premature polyadenylation of the G2 transcript are observed. The phenotypes conditioned by these four mutations demonstrate that the primary role of G2 in C4 leaf blades is to promote bundle sheath cell chloroplast development. C4 photosynthetic enzymes can accumulate in both bundle sheath and mesophyll cells in the absence of G2. In C3 tissue, however, G2 influences both chloroplast differentiation and photosynthetic enzyme accumulation patterns. On the basis of the phenotypic data obtained, a model that postulates how G2 acts to facilitate C4 and C3 patterns of tissue development is proposed.

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