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 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.

Antennal transcriptome analysis and candidate olfactory genes in Crematogaster rogenhoferi

2021 ◽  
pp. 1-12
Author(s):  
Xiang Zhou ◽  
Jixing Guo ◽  
Mingxia Zhang ◽  
Chunxiu Bai ◽  
Zheng Wang ◽  
...  
Keyword(s):  
Biological Control ◽  
Transcriptome Analysis ◽  
Molecular Basis ◽  
Molecular Mechanisms ◽  
Biological Control Agent ◽  
Control Agent ◽  
Vital Role ◽  
Neuron Membrane ◽  
Ionotropic Receptors ◽  
Soft Scale

Abstract Crematogaster rogenhoferi (Hymenoptera: Formicidae), an omnivorous ant, is one of the dominant predatory natural enemies of a soft scale pest, Parasaissetia nigra Nietner (Homoptera: Coccidae), and can effectively control P. nigra populations in rubber forests. Olfaction plays a vital role in the process of predation. However, the information about the molecular mechanism of olfaction-evoked behaviour in C. rogenhoferi is limited. In this study, we conducted antennal transcriptome analysis to identify candidate olfactory genes. We obtained 53,892 unigenes, 16,185 of which were annotated. Based on annotations, we identified 49 unigenes related to chemoreception, including four odourant-binding proteins, three chemosensory proteins, 37 odourant receptors, two odourant ionotropic receptors and three sensory neuron membrane proteins. This is the first report on the molecular basis of the chemosensory system of C. rogenhoferi. The findings provide a basis for elucidating the molecular mechanisms of the olfactory-related behaviours of C. rogenhoferi, which would facilitate a better application of C. rogenhoferi as a biological control agent.

The Molecular basis of Lactose Intolerance

2005 ◽  
Vol 88 (3) ◽  
pp. 157-202 ◽  
Author(s):  
Anthony K. Campbell ◽  
Jonathan P. Waud ◽  
Stephanie B. Matthews
Keyword(s):  
Rheumatoid Arthritis ◽  
Multiple Sclerosis ◽  
Molecular Basis ◽  
Charles Darwin ◽  
Lactose Intolerance ◽  
Anaerobic Bacteria ◽  
Bacterial Toxins ◽  
Systemic Symptoms ◽  
Lactase Gene ◽  
Over 40 Years

A staggering 4000 million people cannot digest lactose, the sugar in milk, properly. All mammals, apart from white Northern Europeans and few tribes in Africa and Asia, lose most of their lactase, the enzyme that cleaves lactose into galactose and glucose, after weaning. Lactose intolerance causes gut and a range of systemic symptoms, though the threshold to lactose varies considerably between ethnic groups and individuals within a group. The molecular basis of inherited hypolactasia has yet to be identified, though two polymorphisms in the introns of a helicase upstream from the lactase gene correlate closely with hypolactasia, and thus lactose intolerance. The symptoms of lactose intolerance are caused by gases and toxins produced by anaerobic bacteria in the large intestine. Bacterial toxins may play a key role in several other diseases, such as diabetes, rheumatoid arthritis, multiple sclerosis and some cancers. The problem of lactose intolerance has been exacerbated because of the addition of products containing lactose to various foods and drinks without being on the label. Lactose intolerance fits exactly the illness that Charles Darwin suffered from for over 40 years, and yet was never diagnosed. Darwin missed something else – the key to our own evolution – the Rubicon some 300 million years ago that produced lactose and lactase in sufficient amounts to be susceptible to natural selection.

scholarly journals Molecular basis of disregulation of programmed lymphocytes’ death in chronic viral infection

2006 ◽  
Vol 5 (2) ◽  
pp. 23-34
Author(s):  
V. V. Novitsky ◽  
N. V. Ryazantseva ◽  
O. B. Zhoukova
Keyword(s):  
Cell Death ◽  
Programmed Cell Death ◽  
Viral Infection ◽  
Immune Cells ◽  
Molecular Basis ◽  
Molecular Mechanisms ◽  
Recent Literature ◽  
Chronic Viral Infection ◽  
Persistent Viruses

The review analyses information from recent literature and results of the authors’ own investigations concerning imbalance of programmed cell death in forming chronic viral infection. Molecular mechanisms of apoptosis modulation of immune cells by persistent viruses are discussed in the article.

scholarly journals Heavily Armed Ancestors: CRISPR Immunity and Applications in Archaea with a Comparative Analysis of CRISPR Types in Sulfolobales

Biomolecules ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1523
Author(s):  
Isabelle Anna Zink ◽  
Erika Wimmer ◽  
Christa Schleper
Keyword(s):  
Comparative Analysis ◽  
Molecular Mechanisms ◽  
Model Organisms ◽  
Special Focus ◽  
Natural Environments ◽  
Type I ◽  
Accessory Proteins ◽  
Type Iii

Prokaryotes are constantly coping with attacks by viruses in their natural environments and therefore have evolved an impressive array of defense systems. Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) is an adaptive immune system found in the majority of archaea and about half of bacteria which stores pieces of infecting viral DNA as spacers in genomic CRISPR arrays to reuse them for specific virus destruction upon a second wave of infection. In detail, small CRISPR RNAs (crRNAs) are transcribed from CRISPR arrays and incorporated into type-specific CRISPR effector complexes which further degrade foreign nucleic acids complementary to the crRNA. This review gives an overview of CRISPR immunity to newcomers in the field and an update on CRISPR literature in archaea by comparing the functional mechanisms and abundances of the diverse CRISPR types. A bigger fraction is dedicated to the versatile and prevalent CRISPR type III systems, as tremendous progress has been made recently using archaeal models in discerning the controlled molecular mechanisms of their unique tripartite mode of action including RNA interference, DNA interference and the unique cyclic-oligoadenylate signaling that induces promiscuous RNA shredding by CARF-domain ribonucleases. The second half of the review spotlights CRISPR in archaea outlining seminal in vivo and in vitro studies in model organisms of the euryarchaeal and crenarchaeal phyla, including the application of CRISPR-Cas for genome editing and gene silencing. In the last section, a special focus is laid on members of the crenarchaeal hyperthermophilic order Sulfolobales by presenting a thorough comparative analysis about the distribution and abundance of CRISPR-Cas systems, including arrays and spacers as well as CRISPR-accessory proteins in all 53 genomes available to date. Interestingly, we find that CRISPR type III and the DNA-degrading CRISPR type I complexes co-exist in more than two thirds of these genomes. Furthermore, we identified ring nuclease candidates in all but two genomes and found that they generally co-exist with the above-mentioned CARF domain ribonucleases Csx1/Csm6. These observations, together with published literature allowed us to draft a working model of how CRISPR-Cas systems and accessory proteins cross talk to establish native CRISPR anti-virus immunity in a Sulfolobales cell.

scholarly journals Exotoxins of Staphylococcus aureus

2000 ◽  
Vol 13 (1) ◽  
pp. 16-34 ◽  
Author(s):  
Martin M. Dinges ◽  
Paul M. Orwin ◽  
Patrick M. Schlievert
Keyword(s):  
Staphylococcus Aureus ◽  
Toxic Shock Syndrome ◽  
Molecular Basis ◽  
Molecular Mechanisms ◽  
Food Poisoning ◽  
Structure And Function ◽  
Toxic Shock ◽  
The Family ◽  
Toxic Shock Syndrome Toxin ◽  
And Function

SUMMARY This article reviews the literature regarding the structure and function of two types of exotoxins expressed by Staphylococcus aureus, pyrogenic toxin superantigens (PTSAgs) and hemolysins. The molecular basis of PTSAg toxicity is presented in the context of two diseases known to be caused by these exotoxins: toxic shock syndrome and staphylococcal food poisoning. The family of staphylococcal PTSAgs presently includes toxic shock syndrome toxin-1 (TSST-1) and most of the staphylococcal enterotoxins (SEs) (SEA, SEB, SEC, SED, SEE, SEG, and SEH). As the name implies, the PTSAgs are multifunctional proteins that invariably exhibit lethal activity, pyrogenicity, superantigenicity, and the capacity to induce lethal hypersensitivity to endotoxin. Other properties exhibited by one or more staphylococcal PTSAgs include emetic activity (SEs) and penetration across mucosal barriers (TSST-1). A detailed review of the molecular mechanisms underlying the toxicity of the staphylococcal hemolysins is also presented.

scholarly journals Insights into histidine kinase activation mechanisms from the monomeric blue light sensor EL346

2019 ◽  
Vol 116 (11) ◽  
pp. 4963-4972 ◽  
Author(s):  
Igor Dikiy ◽  
Uthama R. Edupuganti ◽  
Rinat R. Abzalimov ◽  
Peter P. Borbat ◽  
Madhur Srivastava ◽  
...  
Keyword(s):  
Blue Light ◽  
Conformational Changes ◽  
Histidine Kinase ◽  
Structural Changes ◽  
Molecular Mechanisms ◽  
Catalytic Domain ◽  
Response Regulator ◽  
Phosphoryl Group ◽  
Dark State ◽  
Light Sensing

Translation of environmental cues into cellular behavior is a necessary process in all forms of life. In bacteria, this process frequently involves two-component systems in which a sensor histidine kinase (HK) autophosphorylates in response to a stimulus before subsequently transferring the phosphoryl group to a response regulator that controls downstream effectors. Many details of the molecular mechanisms of HK activation are still unclear due to complications associated with the multiple signaling states of these large, multidomain proteins. To address these challenges, we combined complementary solution biophysical approaches to examine the conformational changes upon activation of a minimal, blue-light–sensing histidine kinase from Erythrobacter litoralis HTCC2594, EL346. Our data show that multiple conformations coexist in the dark state of EL346 in solution, which may explain the enzyme’s residual dark-state activity. We also observe that activation involves destabilization of the helices in the dimerization and histidine phosphotransfer-like domain, where the phosphoacceptor histidine resides, and their interactions with the catalytic domain. Similar light-induced changes occur to some extent even in constitutively active or inactive mutants, showing that light sensing can be decoupled from activation of kinase activity. These structural changes mirror those inferred by comparing X-ray crystal structures of inactive and active HK fragments, suggesting that they are at the core of conformational changes leading to HK activation. More broadly, our findings uncover surprising complexity in this simple system and allow us to outline a mechanism of the multiple steps of HK activation.

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