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41.
Sebastin JaramilloRiveri James Broughton Alexander McVey Teuta Pilizota Matthew Scott Meriem El Karoui 《Molecular systems biology》2022,18(5)
In natural environments, bacteria are frequently exposed to sub‐lethal levels of DNA damage, which leads to the induction of a stress response (the SOS response in Escherichia coli). Natural environments also vary in nutrient availability, resulting in distinct physiological changes in bacteria, which may have direct implications on their capacity to repair their chromosomes. Here, we evaluated the impact of varying the nutrient availability on the expression of the SOS response induced by chronic sub‐lethal DNA damage in E. coli. We found heterogeneous expression of the SOS regulon at the single‐cell level in all growth conditions. Surprisingly, we observed a larger fraction of high SOS‐induced cells in slow growth as compared with fast growth, despite a higher rate of SOS induction in fast growth. The result can be explained by the dynamic balance between the rate of SOS induction and the division rates of cells exposed to DNA damage. Taken together, our data illustrate how cell division and physiology come together to produce growth‐dependent heterogeneity in the DNA damage response. 相似文献
42.
Aline Frville Bndicte Gnangnon Annie Z. Tremp Caroline De Witte Katia Cailliau Alain Martoriati El Moukthar Aliouat Priyanka Fernandes Cerina Chhuon Olivier Silvie Sabrina Marion Ida Chiara Guerrera Johannes T. Dessens Christine Pierrot Jamal Khalife 《Open biology》2022,12(8)
Protein phosphatase 1 (PP1) is a key enzyme for Plasmodium development. However, the detailed mechanisms underlying its regulation remain to be deciphered. Here, we report the functional characterization of the Plasmodium berghei leucine-rich repeat protein 1 (PbLRR1), an orthologue of SDS22, one of the most ancient and conserved PP1 interactors. Our study shows that PbLRR1 is expressed during intra-erythrocytic development of the parasite, and up to the zygote stage in mosquitoes. PbLRR1 can be found in complex with PbPP1 in both asexual and sexual stages and inhibits its phosphatase activity. Genetic analysis demonstrates that PbLRR1 depletion adversely affects the development of oocysts. PbLRR1 interactome analysis associated with phospho-proteomics studies identifies several novel putative PbLRR1/PbPP1 partners. Some of these partners have previously been characterized as essential for the parasite sexual development. Interestingly, and for the first time, Inhibitor 3 (I3), a well-known and direct interactant of Plasmodium PP1, was found to be drastically hypophosphorylated in PbLRR1-depleted parasites. These data, along with the detection of I3 with PP1 in the LRR1 interactome, strongly suggest that the phosphorylation status of PbI3 is under the control of the PP1–LRR1 complex and could contribute (in)directly to oocyst development. This study provides new insights into previously unrecognized PbPP1 fine regulation of Plasmodium oocyst development through its interaction with PbLRR1. 相似文献
43.
Monica Y. Burgos Zepeda Kevin Alessandri Dorothée Murat Chahrazade El Amri Elie Dassa 《Biochimica et Biophysica Acta - Proteins and Proteomics》2010,1804(4):755-761
The Uup protein belongs to a subfamily of soluble ATP-binding cassette (ABC) ATPases that have been implicated in several processes different from transmembrane transport of molecules, such as transposon precise excision. We have demonstrated previously that Escherichia coli Uup is able to bind DNA. DNA binding capacity is lowered in a truncated Uup protein lacking its C-terminal domain (CTD), suggesting a contribution of CTD to DNA binding. In the present study, we characterize the role of CTD in the function of Uup, on its overall stability and in DNA binding. To this end, we expressed and purified isolated CTD and we investigated the structural and functional role of this domain. The results underline that CTD is essential for the function of Uup, is stable and able to fold up autonomously. We compared the DNA binding activities of three versions of the protein (Uup, UupΔCTD and CTD) by an electrophoretic mobility shift assay. CTD is able to bind DNA although less efficiently than intact Uup and UupΔCTD. These observations suggest that CTD is an essential domain that contributes directly to the DNA binding ability of Uup. 相似文献
44.
R.S. Mohammed A.H. Abou Zeid S.S. El Hawary A.A. Sleem W.E. Ashour 《Saudi Journal of Biological Sciences》2014,21(6):547-553
Gleditsia triacanthos L. is a deciduous tree belonging to the family Fabaceae. It possesses important biological activities as anti-mutagenic, anticancer, cytotoxic and treating rheumatoid arthritis. The total ethanol extract (EtOHE) and successive extracts (petroleum ether, chloroform, ethyl acetate, and aqueous ethanol) were prepared from the leaves. Eight flavone glycosides and two flavone aglycones named vicenin-I (1), vitexin (2), isovitexin (3), orientin (4), isoorientin (5), luteolin-7-O-ß-glucopyranoside (6), luteolin-7-O-ß-galactopyranoside (7), apigenin-7-O-ß-glucopyranoside (8), luteolin (9) and apigenin (10) were isolated from the aqueous ethanol extract of G. triacanthos L. leaves. Potent cytotoxic activity of the EtOHE extract was observed against the liver (IC50 = 1.68 μg), breast (IC50 = 0.74 μg), cervix (IC50 = 1.28 μg), larynx (IC50 = 0.67 μg) and colon (IC50 = 2.50 μg) cancer cell lines. Cytotoxic activity of compounds 2, 4, 6 and 8 against, the liver, breast and colon cancer cell lines was also proved. Evaluation of the in-vivo antioxidant activity of the EtOHE and successive extracts revealed that the highest activity was exhibited by 100 mg of EtOHE (97.89% potency) as compared with vitamin E (100% potency). Compound 6 showed 91.8% free radical scavenging activity. 相似文献
45.
El Ghazi I Martin BL Armitage IM 《Experimental biology and medicine (Maywood, N.J.)》2006,231(9):1500-1506
Metallothionein (MT)-3, originally called growth inhibitory factor (GIF), was initially identified through its ability to inhibit the growth of neuronal cells in the presence of brain extract. MT-3 is the brain specific isoform of the MT family whose specific biological activity associates it with neurological disorders. Indeed, studies report that MT-3 is decreased by ~30% in brains of patients with Alzheimer disease (AD). Furthermore, many lines of evidence suggest that MT-3 engages in specific protein interactions. To address this, we conducted immunoaffinity chromatography experiments using an immobilized anti-mouse MT-3 antibody. We identified five associated proteins from the pool of sixteen recovered using mass spectrometry and tandem mass spectrometry after in-gel trypsin digestion of bands from the affinity chromatography. The proteins identified were: heat shock protein 84 (HSP84), heat shock protein 70 (HSP70), dihydropyrimidinase-like protein-2 (DRP-2), creatine kinase (CK) and beta-actin. Coimmunoprecipitation experiments, also conducted on whole mouse brain extract using the anti-mouse MT-3 antibody along with commercially available antibodies against HSP84 and CK, confirmed that these three proteins were in a single protein complex. Immunohistochemical experiments were then conducted on the perfused mouse brain that confirmed the in situ colocalization of CK and MT-3 in the hippocampus region. These data provide new insights into the involvement of MT-3 in a multiprotein complex, which will be used to understand the biological activity of MT-3 and its role in neurological disease. 相似文献
46.
Effects of cadmium and copper on peroxidase, NADH oxidase and IAA oxidase activities in cell wall, soluble and microsomal membrane fractions of pea roots 总被引:11,自引:0,他引:11
Twelve-day-old seedlings of pea (Pisum sativum L.) that were treated for 4 days by 20 and 100 micromol/l Cd(NO3)2 or CuSO4 showed a growth reduction in all organs. From root protein extracts, the activities of guaiacol peroxidase (GPX; EC 1.11.1.7), ascorbate peroxidase (APX; EC 1.11.1.11), coniferyl alcohol peroxidase (CAPX), NADH oxidase, and indole-3-acetic acid (IAA) oxidase were measured in covalently--and ionically--[symbol: see text] bound cell wall, soluble, and microsomal membrane fractions. With the exception of 20 micromol/l Cu, metal treatments enhanced GPX activity in all fractions. Only IAA oxidase activity was metal-elevated in the covalently bound cell wall fraction, while the ionic one showed Cd stimulation for all assayed enzymic activities. These effects were not entirely observed in Cu-treated plants, since APX and IAA oxidase activities were only enhanced in this fraction. However, soluble extract showed stimulation of APX activity, while in the microsomal fraction metal exposure also increased the activities of CAPX and NADH oxidase. Differential responses of root cell fractions to the presence of cadmium and copper ions are discussed in regard to the contribution of their enzymic capacities in antioxidant, lignification, and auxin degradation pathways. Comparisons between metals and dose effects are also underlined. 相似文献
47.
Pyrolysis of olive residue and sugar cane bagasse: non-isothermal thermogravimetric kinetic analysis
Thermal degradation and kinetics for olive residue and sugar cane bagasse have been evaluated under dynamic conditions in the presence of nitrogen atmosphere, using a non-isothermal thermogravimetric method (TGA). The effect of heating rate was evaluated in the range of 2-50 K min(-1) providing significant parameters for the fingerprinting of the biomass. The DTG plot for the olive residue and sugar cane bagasse clearly shows that the bagasse begins to degrade at 473 K and exhibits two major peaks. The initial mass-loss was associated with hemicellulose pyrolysis and responsible for the first peak (538-543 K) whereas cellulose pyrolysis was initiated at higher temperatures and responsible for the second peak (600-607 K). The two biomass mainly devolatilized around 473-673 K, with total volatile yield of about 70-75%. The char in final residue was about 19-26%. Mass loss and mass loss rates were strongly affected by heating rate. It was found that an increase in heating rate resulted in a shift of thermograms to higher temperatures. Ozawa-Flynn-Wall and Vyazovkin methods were applied to determine apparent activation energy to the olive residue and sugar cane bagasse. Two different steps were detected with apparent activation energies in the 10-40% conversion range have a value of 153-162 kJ mol(-1) and 168-180 kJ mol(-1) for the hemicellulose degradation of olive residue and sugar cane bagasse, respectively. In the 50-80% conversion range, this value is 204-215 kJ mol(-1) and 231-240 kJ mol(-1) for the cellulose degradation of olive residue and sugar cane bagasse, respectively. 相似文献
48.
Marianna Małek Bożena Bogusz Paulina Mrowiec Mariusz Szuta Maciej Opach Iwona Skiba-Kurek Paweł Nowak Karolina Klesiewicz Alicja Budak Elżbieta Karczewska 《Revista iberoamericana de micología》2018,35(3):140-146
Background
Fungal rhinosinusitis has become an increasingly recognized disease, being Aspergillus species responsible for most of the cases. Its diagnosis is quite difficult because of the non-specific symptoms and low sensitivity of the current diagnostic methods.Aims
An Aspergillus-specific nested polymerase chain reaction (PCR) assay using biopsy specimens taken from the maxillary sinuses was performed in order to assess its usefulness. Conventional diagnostic methods (histology and culture) were also carried out.Methods
A case–control study was performed in the Institute of Stomatology, Jagiellonian University in Kraków, between 2011 and 2014. The case group consisted of 21 patients with suspected rhinosinusal mycetoma while the control group included 46 patients with no suspicion of fungal rhinosinusitis. The two-step PCR assay amplified an Aspergillus specific portion of the 18S rRNA gene. Interval estimation of sensitivity, specificity, positive (PPV) and negative (NPV) predictive values were calculated to assess the diagnostic test performance. The agreement between the PCR and the other tests was evaluated using the Kappa coefficient (k).Results
Ninety percent of the samples obtained from patients diagnosed with mycetoma yielded positive PCR results. The PCR showed almost perfect concordance with histology (k = 0.88). Sensitivity, specificity, PPV and NPV estimates were 90%; 95% CI: (55.5–99.7%), 98.3%; 95% CI: (90.9–100%), 90%; 95% CI: (55.5–99.7%) and 98.3%; 95% CI: (90.9–100%), respectively. One clinical sample showed growth of Aspergillus fumigatus and positive PCR despite the negative histological examination.Conclusions
Nested PCR assay is a promising diagnostic tool to evaluate the presence of Aspergillus in the tissue of maxillary sinus from patients with suspicion of sinus aspergillosis. 相似文献49.
Mohamed A. Farag Dalia A. Al‐Mahdy Riham Salah El Dine Sherifa Fahmy Aymen Yassin Andrea Porzel Wolfgang Brandt 《化学与生物多样性》2015,12(6):955-962
Bacterial wilts of potato, tomato, pepper, and or eggplant caused by Ralstonia solanacearum are among the most serious plant diseases worldwide. In this study, the issue of developing bactericidal agents from natural sources against R. solanacearum derived from plant extracts was addressed. Extracts prepared from 25 plant species with antiseptic relevance in Egyptian folk medicine were screened for their antimicrobial properties against the potato pathogen R. solancearum by using the disc‐zone inhibition assay and microtitre plate dilution method. Plants exhibiting notable antimicrobial activities against the tested pathogen include extracts from Acacia arabica and Punica granatum. Bioactivity‐guided fractionation of A. arabica and P. granatum resulted in the isolation of bioactive compounds 3,5‐dihydroxy‐4‐methoxybenzoic acid and gallic acid, in addition to epicatechin. All isolates displayed significant antimicrobial activities against R. solanacearum (MIC values 0.5–9 mg/ml), with 3,5‐dihydroxy‐4‐methoxybenzoic acid being the most effective one with a MIC value of 0.47 mg/ml. We further performed a structure–activity relationship (SAR) study for the inhibition of R. solanacearum growth by ten natural, structurally related benzoic acids. 相似文献
50.
Durgeau A El Hage F Vergnon I Validire P de Montpréville V Besse B Soria JC van Hall T Mami-Chouaib F 《Journal of immunology (Baltimore, Md. : 1950)》2011,187(11):5532-5539
Decreased antigenicity of cancer cells is a major problem in tumor immunology. This is often acquired by an expression defect in the TAP. However, it has been reported that certain murine Ags appear on the target cell surface upon impairment of TAP expression. In this study, we identified a human CTL epitope belonging to this Ag category. This epitope is derived from preprocalcitonin (ppCT) signal peptide and is generated within the endoplasmic reticulum by signal peptidase and signal peptide peptidase. Lung cancer cells bearing this antigenic peptide displayed low levels of TAP, but restoration of their expression by IFN-γ treatment or TAP1 and TAP2 gene transfer abrogated ppCT Ag presentation. In contrast, TAP upregulation in the same tumor cells increased their recognition by proteasome/TAP-dependent peptide-specific CTLs. Thus, to our knowledge, ppCT(16-25) is the first human tumor epitope whose surface expression requires loss or downregulation of TAP. Lung tumors frequently display low levels of TAP molecules and might thus be ignored by the immune system. Our results suggest that emerging signal peptidase-generated peptides represent alternative T cell targets, which permit CTLs to destroy TAP-impaired tumors and thus overcome tumor escape from CD8(+) T cell immunity. 相似文献