scholarly journals Control of Flagellar Gene Regulation in Legionella pneumophila and Its Relation to Growth Phase

2009 ◽  
Vol 192 (2) ◽  
pp. 446-455 ◽  
Author(s):  
Christiane Albert-Weissenberger ◽  
Tobias Sahr ◽  
Odile Sismeiro ◽  
Jörg Hacker ◽  
Klaus Heuner ◽  
...  
Keyword(s):  
Legionella Pneumophila ◽  
Environmental Changes ◽  
Bacterial Pathogen ◽  
Class Ii ◽  
Transcriptional Level ◽  
Class Iii ◽  
Phenotypic Analysis ◽  
Independent Manner ◽  
Genes Encoding ◽  
Class Iii Genes

ABSTRACT The bacterial pathogen Legionella pneumophila responds to environmental changes by differentiation. At least two forms are well described: replicative bacteria are avirulent; in contrast, transmissive bacteria express virulence traits and flagella. Phenotypic analysis, Western blotting, and electron microscopy of mutants of the regulatory genes encoding RpoN, FleQ, FleR, and FliA demonstrated that flagellin expression is strongly repressed and that the mutants are nonflagellated in the transmissive phase. Transcriptome analyses elucidated that RpoN, together with FleQ, enhances transcription of 14 out of 31 flagellar class II genes, which code for the basal body, hook, and regulatory proteins. Unexpectedly, FleQ independent of RpoN enhances the transcription of fliA encoding sigma 28. Expression analysis of a fliA mutant showed that FliA activates three out of the five remaining flagellar class III genes and the flagellar class IV genes. Surprisingly, FleR does not induce but inhibits expression of at least 14 flagellar class III genes on the transcriptional level. Thus, we propose that flagellar class II genes are controlled by FleQ and RpoN, whereas the transcription of the class III gene fliA is controlled in a FleQ-dependent but RpoN-independent manner. However, RpoN and FleR might influence flagellin synthesis on a posttranscriptional level. In contrast to the commonly accepted view that enhancer-binding proteins such as FleQ always interact with RpoN to fullfill their regulatory functions, our results strongly indicate that FleQ regulates gene expression that is RpoN dependent and RpoN independent. Finally, FliA induces expression of flagellar class III and IV genes leading to the complete synthesis of the flagellum.

scholarly journals A Trypanosoma cruzi Zinc Finger protein that controls expression of epimastigote specific genes and affects metacyclogenesis

2020 ◽  
Author(s):  
Thais Silva Tavares ◽  
Fernanda Lins Brandão Mügge ◽  
Viviane Grazielle-Silva ◽  
Bruna Mattioly Valente ◽  
Wanessa Moreira Goes ◽  
...  
Keyword(s):  
Gene Expression ◽  
Trypanosoma Cruzi ◽  
Zinc Finger ◽  
Rna Binding ◽  
Environmental Changes ◽  
Zinc Finger Protein ◽  
Negative Regulator ◽  
Transcriptional Level ◽  
Control Of Gene Expression ◽  
Genes Encoding

SummaryTrypanosoma cruzi has three biochemically and morphologically distinct developmental stages that are programed to rapidly respond to environmental changes the parasite faces during its life cycle. Unlike other eukaryotes, Trypanosomatid genomes contain protein coding genes that are transcribed into polycistronic pre-mRNAs and control of gene expression relies on mechanisms acting at the post-transcriptional level. Transcriptome analyses comparing epimastigote, trypomastigote and intracellular amastigote stages revealed changes in gene expression that reflect the parasite adaptation to distinct environments. Several genes encoding RNA binding proteins (RBP), known to act as key post-transcriptional regulatory factors, were also differentially expressed. We characterized one T. cruzi RBP (TcZH3H12) that contains a zinc finger domain, and whose transcripts are upregulated in epimastigotes compared to trypomastigotes and amastigotes. TcZC3H12 knockout epimastigotes showed decreased growth rates and increased capacity to differentiate into metacyclic trypomastigotes. Comparative transcriptome analysis revealed a TcZC3H12-dependent expression of epimastigote specific genes encoding amino acid transporters and proteins associated with differentiation (PAD), among others. RNA immunoprecipitation assays showed that transcripts from the PAD family interact with TcZC3H12. Taken together, these findings suggest that TcZC3H12 positively regulates the expression of genes involved in epimastigote proliferation and also acts as a negative regulator of metacyclogenesis.

scholarly journals Cloning of the Arabidopsis and Rice Formaldehyde Dehydrogenase Genes: Implications for the Origin of Plant ADH Enzymes

Genetics ◽  
1997 ◽  
Vol 146 (3) ◽  
pp. 1131-1141 ◽  
Author(s):  
R Dolferus ◽  
J C Osterman ◽  
W J Peacock ◽  
E S Dennis
Keyword(s):  
Nucleic Acid ◽  
Amino Acid Sequences ◽  
Metabolic Function ◽  
Formaldehyde Dehydrogenase ◽  
Class Iii ◽  
Alcohol Fermentation ◽  
Substrate Specificities ◽  
Adh Genes ◽  
Genes Encoding ◽  
Class Iii Genes

This article reports the cloning of the genes encoding the Arabidopsis and rice class III ADH enzymes, members of the alcohol dehydrogenase or medium chain reductase/dehydrogenase superfamily of proteins with glutathione-dependent formaldehyde dehydrogenase activity (GSH-FDH). Both genes contain eight introns in exactly the same positions, and these positions are conserved in plant ethanolactive Adh genes (class P). These data provide further evidence that plant class P genes have evolved from class III genes by gene duplication and acquisition of new substrate specificities. The position of introns and similarities in the nucleic acid and amino acid sequences of the different classes of ADH enzymes in plants and humans suggest that plant and animal class I11 enzymes diverged before they duplicated to give rise to plant and animal ethanol-active ADH enzymes. Plant class P ADH enzymes have gained substrate specificities and evolved promoters with different expression properties, in keeping with their metabolic function as part of the alcohol fermentation pathway.

Regulation of Histone Deacetylases by MicroRNAs in Bone

2019 ◽  
Vol 20 (4) ◽  
pp. 356-367 ◽  
Author(s):  
S. Shreya ◽  
D. Malavika ◽  
V. Raj Priya ◽  
N. Selvamurugan
Keyword(s):  
Histone Deacetylases ◽  
Osteoblast Differentiation ◽  
Essential Role ◽  
Class Ii ◽  
Signaling Cascades ◽  
Transcriptional Level ◽  
Class Iii ◽  
Regulatory Factors ◽  
Non Coding Rnas ◽  
Class Iv

Formation of new bone by osteoblasts is mediated via the activation of signaling pathways, such as TGF-β, BMP, and Wnt. A number of transcription factors participate in the signaling cascades that are tightly regulated by other regulatory factors. Histone deacetylases (HDACs) are one such class of regulatory factors that play an essential role in influencing chromatin architecture and regulate the expression of the genes that play a role in osteoblast differentiation by the mechanism of deacetylation. Four classes of HDACs have been identified namely, class I, class II A, class II B, class III and class IV. MicroRNAs (miRNAs) are small fragments of non-coding RNAs typically 19-25 nucleotides long that target mRNAs to upregulate or downregulate gene expression at a post-transcriptional level. A number of miRNAs that target HDACs in bone have been recently reported. Hence, in this review, we elaborate on the various miRNAs that target the different classes of HDACs and impact of the same on osteogenesis.

The dorsal-open group gene raw is required for restricted DJNK signaling during closure

Development ◽  
1999 ◽  
Vol 126 (21) ◽  
pp. 4913-4923 ◽  
Author(s):  
C.L. Byars ◽  
K.L. Bates ◽  
A. Letsou
Keyword(s):  
Leading Edge ◽  
Class Ii ◽  
Signaling Molecules ◽  
Open Group ◽  
Gene Products ◽  
The Novel ◽  
Class Iii ◽  
Class Iii Genes ◽  
Novel Protein

During dorsal closure in Drosophila melanogaster, cells of the lateral epidermis migrate over the amnioserosa to encase the embryo. At least three classes of dorsal-open group gene products are necessary for this morphogenetic movement. Class I genes code for structural proteins that effect changes in epidermal cell shape and motility. Class II and III genes code for regulatory components of closure: Class II genes encode Drosophila Jun amino (N)-terminal kinase (DJNK) signaling molecules and Class III genes encode Decapentaplegic-mediated signaling molecules. All characterized dorsal-open group gene products function in the epidermis. Here we report a molecular and genetic characterization of raw, a newly defined member of the Class II dorsal-open group genes. We show that the novel protein encoded by raw is required for restriction of DJNK signaling to leading edge epidermal cells as well as for proper development of the amnioserosa. Taken together, our results demonstrate a role for Raw in restriction of epidermal signaling during closure and suggest that this effect may be mediated via the amnioserosa.

Genomic localization of the human gene encoding Dr1 a negative modulator of transcription of class II and class III genes

1996 ◽  
Vol 75 (2-3) ◽  
pp. 186-189 ◽  
Author(s):  
M. Purrello ◽  
C. DiPietro ◽  
A. Rapisarda ◽  
A. Viola ◽  
C. Corsaro ◽  
...  
Keyword(s):  
Human Gene ◽  
Class Ii ◽  
Class Iii ◽  
Gene Encoding ◽  
Class Iii Genes ◽  
Negative Modulator

scholarly journals Atypical Bacterial Pathogens and Small-Vessel Leukocytoclastic Vasculitis of the Skin in Children: Systematic Literature Review

Pathogens ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 31
Author(s):  
Céline Betti ◽  
Pietro Camozzi ◽  
Viola Gennaro ◽  
Mario G. Bianchetti ◽  
Martin Scoglio ◽  
...  
Keyword(s):  
Mycoplasma Pneumoniae ◽  
Legionella Pneumophila ◽  
Leukocytoclastic Vasculitis ◽  
Systemic Vasculitis ◽  
Bacterial Pathogen ◽  
Small Vessel ◽  
Small Vessel Vasculitis ◽  
Systemic Involvement ◽  
Symptomatic Disease ◽  
Atypical Pathogen

Leukocytoclastic small-vessel vasculitis of the skin (with or without systemic involvement) is often preceded by infections such as common cold, tonsillopharyngitis, or otitis media. Our purpose was to document pediatric (≤18 years) cases preceded by a symptomatic disease caused by an atypical bacterial pathogen. We performed a literature search following the Preferred Reporting of Systematic Reviews and Meta-Analyses guidelines. We retained 19 reports including 22 cases (13 females and 9 males, 1.0 to 17, median 6.3 years of age) associated with a Mycoplasma pneumoniae infection. We did not find any case linked to Chlamydophila pneumoniae, Chlamydophila psittaci, Coxiella burnetii, Francisella tularensis, or Legionella pneumophila. Patients with a systemic vasculitis (N = 14) and with a skin-limited (N = 8) vasculitis did not significantly differ with respect to gender and age. The time to recovery was ≤12 weeks in all patients with this information. In conclusion, a cutaneous small-vessel vasculitis with or without systemic involvement may occur in childhood after an infection caused by the atypical bacterial pathogen Mycoplasma pneumoniae. The clinical picture and the course of cases preceded by recognized triggers and by this atypical pathogen are indistinguishable.

scholarly journals Environmental Cadmium Exposure and Dental Indices in Orthodontic Patients

Healthcare ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 413
Author(s):  
Hui-Ling Chen ◽  
Jason Chen-Chieh Fang ◽  
Chia-Jung Chang ◽  
Ti-Feng Wu ◽  
I-Kuan Wang ◽  
...  
Keyword(s):  
Cadmium Concentration ◽  
Class Ii ◽  
Cadmium Exposure ◽  
Class I ◽  
P Value ◽  
Tooth Decay ◽  
Class Iii ◽  
Orthodontic Patients ◽  
Urine Cadmium ◽  
The Mean

Background. Previous studies have shown that environmental cadmium exposure could disrupt salivary gland function and is associated with dental caries and reduced bone density. Therefore, this cross-sectional study attempted to determine whether tooth decay with tooth loss following cadmium exposure is associated with some dental or skeletal traits such as malocclusions, sagittal skeletal pattern, and tooth decay. Methods. Between August 2019 and June 2020, 60 orthodontic patients with no history of previous orthodontics, functional appliances, or surgical treatment were examined. The patients were stratified into two groups according to their urine cadmium concentrations: high (>1.06 µg/g creatinine, n = 28) or low (<1.06 µg/g creatinine, n = 32). Results. The patients were 25.07 ± 4.33 years old, and most were female (female/male: 51/9 or 85%). The skeletal relationship was mainly Class I (48.3%), followed by Class II (35.0%) and Class III (16.7%). Class I molar relationships were found in 46.7% of these patients, Class II molar relationships were found in 15%, and Class III molar relationships were found in 38.3%. The mean decayed, missing, and filled surface (DMFS) score was 8.05 ± 5.54, including 2.03 ± 3.11 for the decayed index, 0.58 ± 1.17 for the missing index, and 5.52 ± 3.92 for the filled index. The mean index of complexity outcome and need (ICON) score was 53.35 ± 9.01. The facial patterns of these patients were within the average low margin (26.65 ± 5.53 for Frankfort–mandibular plane angle (FMA)). There were no significant differences in the above-mentioned dental indices between patients with high urine cadmium concentrations and those with low urine cadmium concentrations. Patients were further stratified into low (<27, n = 34), average (27–34, n = 23), and high (>34, n = 3) FMA groups. There were no statistically significant differences in the urine cadmium concentration among the three groups. Nevertheless, a marginally significant p-value of 0.05 for urine cadmium concentration was noted between patients with low FMA and patients with high FMA. Conclusion. This analysis found no association between environmental cadmium exposure and dental indices in our orthodontic patients.

scholarly journals Exposure to low doses of pesticides induces an immune response and the production of nitric oxide in honeybees

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Merle T. Bartling ◽  
Susanne Thümecke ◽  
José Herrera Russert ◽  
Andreas Vilcinskas ◽  
Kwang-Zin Lee
Keyword(s):  
Nitric Oxide ◽  
Immune Responses ◽  
Bacterial Pathogen ◽  
Wild Plants ◽  
P450 Monooxygenase ◽  
Abiotic Stressors ◽  
Genes Encoding ◽  
Pesticides Exposure ◽  
Colony Survival ◽  
Oxide Synthase

AbstractHoneybees are essential pollinators of many agricultural crops and wild plants. However, the number of managed bee colonies has declined in some regions of the world over the last few decades, probably caused by a combination of factors including parasites, pathogens and pesticides. Exposure to these diverse biotic and abiotic stressors is likely to trigger immune responses and stress pathways that affect the health of individual honeybees and hence their contribution to colony survival. We therefore investigated the effects of an orally administered bacterial pathogen (Pseudomonas entomophila) and low-dose xenobiotic pesticides on honeybee survival and intestinal immune responses. We observed stressor-dependent effects on the mean lifespan, along with the induction of genes encoding the antimicrobial peptide abaecin and the detoxification factor cytochrome P450 monooxygenase CYP9E2. The pesticides also triggered the immediate induction of a nitric oxide synthase gene followed by the delayed upregulation of catalase, which was not observed in response to the pathogen. Honeybees therefore appear to produce nitric oxide as a specific defense response when exposed to xenobiotic stimuli. The immunity-related and stress-response genes we tested may provide useful stressor-dependent markers for ecotoxicological assessment in honeybee colonies.

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