scholarly journals Photoregulation of Cellular Morphology during Complementary Chromatic Adaptation Requires Sensor-Kinase-Class Protein RcaE in Fremyella diplosiphon

2008 ◽  
Vol 190 (11) ◽  
pp. 4069-4074 ◽  
Author(s):  
Juliana R. Bordowitz ◽  
Beronda L. Montgomery
Keyword(s):  
Mutant Strain ◽  
Molecular Basis ◽  
Green Light ◽  
Cellular Morphology ◽  
Chromatic Adaptation ◽  
Sensor Kinase ◽  
Wild Type ◽  
Fremyella Diplosiphon ◽  
Complementary Chromatic Adaptation ◽  
Biochemical Analyses

ABSTRACT We used wild-type UTEX481; SF33, a shortened-filament mutant strain that shows normal complementary chromatic adaptation pigmentation responses; and FdBk14, an RcaE-deficient strain that lacks light-dependent pigmentation responses, to investigate the molecular basis of the photoregulation of cellular morphology in the cyanobacterium Fremyella diplosiphon. Detailed microscopic and biochemical analyses indicate that RcaE is required for the photoregulation of cell and filament morphologies of F. diplosiphon in response to red and green light.

scholarly journals FdTonB is involved in the photoregulation of cellular morphology during complementary chromatic adaptation in Fremyella diplosiphon

Microbiology ◽  
2010 ◽  
Vol 156 (3) ◽  
pp. 731-741 ◽  
Author(s):  
Bagmi Pattanaik ◽  
Beronda L. Montgomery
Keyword(s):  
Transmembrane Domain ◽  
Sequence Similarity ◽  
Green Light ◽  
Cellular Morphology ◽  
Chromatic Adaptation ◽  
Cell Width ◽  
Fremyella Diplosiphon ◽  
Complementary Chromatic Adaptation ◽  
Rich Domain ◽  
Sequence Similarity Analysis

We have characterized a Fremyella diplosiphon TonB protein (FdTonB) and investigated its function during complementary chromatic adaptation. Sequence similarity analysis of FdTonB (571 aa) led to identification of several conserved domains characteristic of TonB proteins, including an N-terminal transmembrane domain, a central proline-rich spacer and a C-terminal TonB-related domain (TBRD). We identified a novel glycine-rich domain containing (Gly-X) n repeats. To assess FdTonB function, we constructed a ΔtonB mutant through homologous recombination based upon truncation of the central proline-rich spacer, glycine-rich domain and TBRD. Our ΔtonB mutant exhibited an aberrant cellular morphology under green light, with expanded cell width compared to the parental wild-type (WT) strain. The cellular morphology of the ΔtonB mutant recovered upon WT tonB expression. Interestingly, tonB expression was found to be independent of RcaE. As ΔtonB and WT strains respond in the same way when grown under iron-replete versus iron-limited conditions, our results suggest that FdTonB is not involved in the classic TonB function of mediating cellular adaptation to iron limitation, but exhibits a novel function related to the photoregulation of cellular morphology in F. diplosiphon.

Shedding new light on the regulation of complementary chromatic adaptation

2008 ◽  
Vol 3 (4) ◽  
pp. 351-358 ◽  
Author(s):  
Beronda Montgomery
Keyword(s):  
Molecular Basis ◽  
Molecular Mechanisms ◽  
Cellular Morphology ◽  
Chromatic Adaptation ◽  
Natural Environments ◽  
Complementary Chromatic Adaptation ◽  
Light Sensing ◽  
Central Elements ◽  
Over 40 Years

AbstractComplementary chromatic adaptation (CCA) is a light-dependent acclimation process that occurs in cyanobacteria and likely is related to increased fitness of these organisms in natural environments. Although CCA has been studied for over 40 years, significant advances in our understanding of the molecular foundations of CCA are still emerging. In this minireview, I explore recently reported developments that include novel insights into the molecular mechanisms utilized in the photoregulation of pigmentation and the molecular basis of light-dependent changes in cellular morphology, which are central elements of the process of CCA. I also discuss future avenues of study that are expected to lead to additional progress in our understanding of CCA and our general appreciation of light sensing and photomorphogenesis in cyanobacteria.

scholarly journals A Single Amino Acid at Residue 188 of Hexon Protein is Responsible for the Pathogenicity of the Emerging Novel Fowl Adenovirus 4

2021 ◽  
Author(s):  
Yu Zhang ◽  
Aijing Liu ◽  
Yanan Wang ◽  
Hongyu Cui ◽  
Yulong Gao ◽  
...  
Keyword(s):  
Amino Acid ◽  
Mutant Strain ◽  
Molecular Basis ◽  
Type Strain ◽  
Wild Type Strain ◽  
Wild Type ◽  
Live Attenuated Vaccine ◽  
Hexon Protein

Since 2015, severe hydropericardium-hepatitis syndrome (HHS) associated with a novel fowl adenovirus 4 (FAdV-4) has emerged in China, representing a new challenge for the poultry industry. Although various highly pathogenic FAdV-4 strains have been isolated, the virulence factor and the pathogenesis of novel FAdV-4 are unclear. In our previous studies, we reported that a large genomic deletion (1966 bp) is not related to increased virulence. In this study, two recombinant chimeric viruses, rHN20 strain and rFB2 strain, were generated from a highly pathogenic FAdV-4 strain by replacing hexon or fiber-2 gene of a non-pathogenic FAdV-4, respectively. Both chimeric strains showed similar titers to the wild type strain in vitro . Notably, rFB2 and the wild type strain induced 100% mortality, while no mortality or clinical signs appeared in chickens inoculated with rHN20, indicating that hexon, but not fiber-2, determines the novel FAdV-4 virulence. Furthermore, an R188I mutation in the hexon protein identified residue 188 as the key amino acid for the reduced pathogenicity. The rR188I mutant strain was significantly neutralized by chicken serum in vitro and in vivo , whereas the wild type strain was able to replicate efficiently. Finally, the immunogenicity of the rescued rR188I was investigated. Non-pathogenic rR188I provided full protection against lethal FAdV-4 challenge. Collectively, these findings provide an in-depth understanding of the molecular basis of novel FAdV-4 pathogenicity and present rR188I as a potential live attenuated vaccine candidate or a novel vaccine vector for HHS vaccines. Importance HHS associated with a novel FAdV-4 infection in chickens has caused huge economic losses to the poultry industry in China since 2015. The molecular basis for the increased virulence remains largely unknown. Here, we demonstrate that the hexon gene is vital for FAdV-4 pathogenicity. Furthermore, we show that the amino acid residue at position 188 of the hexon protein is responsible for pathogenicity. Importantly, the rR188I mutant strain was neutralized by chicken serum in vitro and in vivo , whereas the wild type strain was not. Further, the rR188I mutant strain provided complete protection against FAdV-4 challenge. Our results provide a molecular basis of the increased virulence of novel FAdV-4. We propose that the rR188I mutant is a potential live attenuated vaccine against HHS and a new vaccine vector for HHS-combined vaccines.

A proteomic approach to the analysis of the components of the phycobilisomes from two cyanobacteria with complementary chromatic adaptation: Fremyella diplosiphon UTEX B590 and Tolypothrix PCC 7601

2012 ◽  
Vol 114 (1) ◽  
pp. 43-58 ◽  
Author(s):  
Bertha Pérez-Gómez ◽  
Guillermo Mendoza-Hernández ◽  
Tecilli Cabellos-Avelar ◽  
Lourdes Elizabeth Leyva-Castillo ◽  
Emma Berta Gutiérrez-Cirlos ◽  
...  
Keyword(s):  
Chromatic Adaptation ◽  
Fremyella Diplosiphon ◽  
Complementary Chromatic Adaptation ◽  
Proteomic Approach

scholarly journals COMPLEMENTARY CHROMATIC ADAPTATION IN A FILAMENTOUS BLUE-GREEN ALGA

1973 ◽  
Vol 58 (2) ◽  
pp. 419-435 ◽  
Author(s):  
Allen Bennett ◽  
Lawrence Bogorad
Keyword(s):  
De Novo ◽  
Red Light ◽  
Experimental System ◽  
Chromatic Adaptation ◽  
Fluorescent Light ◽  
Filament Length ◽  
Fremyella Diplosiphon ◽  
Complementary Chromatic Adaptation ◽  
Metabolic Degradation ◽  
Light Transfer

Fluorescent and red light environments generate greatly different patterns of pigmentation and morphology in Fremyella diplosiphon. Most strikingly, red-illuminated cultures contain no measurable C-phycoerythrin and have a mean filament length about 10 times shorter than fluorescent-illuminated cultures. C-phycoerythrin behaves as a photoinducible constituent of this alga. Spectrophotometric and immunochemical procedures were devised so that C-phycoerythrin metabolism could be studied quantitatively with [14C]-phenylalanine pulse-chased cultures. Transfer of red-illuminated cultures to fluorescent light initiates C-phycoerythrin production by essentially de novo synthesis. C-phycoerythrin is not degraded to any significant extent in cultures continuously illuminated with fluorescent light. Transfer of fluorescent-illuminated cultures to red light causes an abrupt cessation of C-phycoerythrin synthesis. The C-phycoerythrin content of cultures adapting to red light decreases and subsequently becomes constant. Loss of C-phycoerythrin is not brought about by metabolic degradation, but rather by a decrease in mean filament length which is effected by transcellular breakage. In this experimental system, light influences intracellular C-phycoerythrin levels by regulating the rate of synthesis of the chromoprotein.

scholarly journals A Turquoise Mutant Genetically Separates Expression of Genes Encoding Phycoerythrin and Its Associated Linker Peptides

2002 ◽  
Vol 184 (4) ◽  
pp. 962-970 ◽  
Author(s):  
Laura Ort Seib ◽  
David M. Kehoe
Keyword(s):  
Light Quality ◽  
Sequence Similarity ◽  
Red Light ◽  
Green Light ◽  
Transcript Abundance ◽  
Chromatic Adaptation ◽  
Partial Control ◽  
Complementary Chromatic Adaptation ◽  
Expression Of Genes ◽  
Genes Encoding

ABSTRACT During complementary chromatic adaptation (CCA), cyanobacterial light harvesting structures called phycobilisomes are restructured in response to ambient light quality shifts. Transcription of genes encoding components of the phycobilisome is differentially regulated during this process: red light activates cpcB2A2, whereas green light coordinately activates the cpeCDE and cpeBA operons. Three signal transduction components that regulate CCA have been isolated to date: a sensor-photoreceptor (RcaE) and two response regulators (RcaF and RcaC). Mutations in the genes encoding these components affect the accumulation of both cpcB2A2 and cpeBA gene products. We have isolated and characterized a new pigmentation mutant called Turquoise 1. We demonstrate that this mutant phenotype is due to a dramatic decrease in cpeBA transcript abundance and results from a lesion in the cpeR gene. However, in this mutant cpeCDE RNA levels remain near those found in wild-type cells. Our results show that the coordinate regulation of cpeBA and cpeCDE by green light can be uncoupled by the loss of CpeR, and we furnish the first genetic evidence that different regulatory mechanisms control these two operons. Sequence analysis of CpeR reveals that it shares limited sequence similarity to members of the PP2C class of protein serine/threonine phosphatases. We also demonstrate that cpeBA and cpeCDE retain light quality responsiveness in a mutant lacking the RcaE photoreceptor. This provides compelling evidence for the partial control of CCA through an as-yet-uncharacterized second light quality sensing system.

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