scholarly journals Low Glucose Mediated Fluconazole Tolerance in Cryptococcus neoformans

2021 ◽  
Vol 7 (6) ◽  
pp. 489
Author(s):  
Somanon Bhattacharya ◽  
Natalia Kronbauer Oliveira ◽  
Anne G. Savitt ◽  
Vanessa K. A. Silva ◽  
Rachel B. Krausert ◽  
...  
Keyword(s):  
Cryptococcus Neoformans ◽  
Mitochondrial Function ◽  
Efflux Pump ◽  
Nile Red ◽  
Fold Increase ◽  
Growth Conditions ◽  
Chromosome 1 ◽  
Normal Glucose ◽  
Low Glucose ◽  
Synthetic Media

Chronic meningoencephalitis is caused by Cryptococcus neoformans and is treated in many parts of the world with fluconazole (FLC) monotherapy, which is associated with treatment failure and poor outcome. In the host, C. neoformans propagates predominantly under low glucose growth conditions. We investigated whether low glucose, mimicked by growing in synthetic media (SM) with 0.05% glucose (SMlowglu), affects FLC-resistance. A > 4-fold increase in FLC tolerance was observed in seven C. neoformans strains when minimum inhibitory concentration (MIC) was determined in SMlowglu compared to MIC in SM with normal (2%) glucose (SMnlglu). In SMlowglu, C. neoformans cells exhibited upregulation of efflux pump genes AFR1 (8.7-fold) and AFR2 (2.5-fold), as well as decreased accumulation (2.6-fold) of Nile Red, an efflux pump substrate. Elevated intracellular ATP levels (3.2-fold and 3.4-fold), as well as decreased mitochondrial reactive oxygen species levels (12.8-fold and 17-fold), were found in the presence and absence of FLC, indicating that low glucose altered mitochondrial function. Fluorescence microscopy revealed that mitochondria of C. neoformans grown in SMlowglu were fragmented, whereas normal glucose promoted a reticular network of mitochondria. Although mitochondrial membrane potential (MMP) was not markedly affected in SMlowglu, it significantly decreased in the presence of FLC (12.5-fold) in SMnlglu, but remained stable in SMlowglu-growing C. neoformans cells. Our data demonstrate that increased FLC tolerance in low glucose-growing C. neoformans is the result of increased efflux pump activities and altered mitochondrial function, which is more preserved in SMlowglu. This mechanism of resistance is different from FLC heteroresistance, which is associated with aneuploidy of chromosome 1 (Chr1).

scholarly journals The TonB system in Aeromonas hydrophila NJ-35 is essential for MacA2B2 efflux pump-mediated macrolide resistance

2021 ◽  
Vol 52 (1) ◽  
Author(s):  
Yuhao Dong ◽  
Qing Li ◽  
Jinzhu Geng ◽  
Qing Cao ◽  
Dan Zhao ◽  
...  
Keyword(s):  
Aeromonas Hydrophila ◽  
Efflux Pump ◽  
Fold Increase ◽  
Activity Level ◽  
Macrolide Resistance ◽  
Wild Type ◽  
Iron Deprivation ◽  
Pump Activity ◽  
Tonb System ◽  
Increased Sensitivity

AbstractThe TonB system is generally considered as an energy transporting device for the absorption of nutrients. Our recent study showed that deletion of this system caused a significantly increased sensitivity of Aeromonas hydrophila to the macrolides erythromycin and roxithromycin, but had no effect on other classes of antibiotics. In this study, we found the sensitivity of ΔtonB123 to all macrolides tested revealed a 8- to 16-fold increase compared with the wild-type (WT) strain, but this increase was not related with iron deprivation caused by tonB123 deletion. Further study demonstrated that the deletion of tonB123 did not damage the integrity of the bacterial membrane but did hinder the function of macrolide efflux. Compared with the WT strain, deletion of macA2B2, one of two ATP-binding cassette (ABC) types of the macrolide efflux pump, enhanced the sensitivity to the same levels as those of ΔtonB123. Interestingly, the deletion of macA2B2 in the ΔtonB123 mutant did not cause further increase in sensitivity to macrolide resistance, indicating that the macrolide resistance afforded by the MacA2B2 pump was completely abrogated by tonB123 deletion. In addition, macA2B2 expression was not altered in the ΔtonB123 mutant, indicating that any influence of TonB on MacA2B2-mediated macrolide resistance was at the pump activity level. In conclusion, inactivation of the TonB system significantly compromises the resistance of A. hydrophila to macrolides, and the mechanism of action is related to the function of MacA2B2-mediated macrolide efflux.

RADT-28. RECURRENT MENINGIOMA WITH 1p/22q SOMATIC MUTATION OF GNAS: A CASE REPORT

2021 ◽  
Vol 23 (Supplement_6) ◽  
pp. vi47-vi47
Author(s):  
Weiping Hong ◽  
Lei Wen ◽  
Changguo Shan ◽  
Minting Ye ◽  
yanying Yang ◽  
...  
Keyword(s):  
Somatic Mutation ◽  
Molecular Diagnosis ◽  
Treatment Plan ◽  
Fold Increase ◽  
Chromosome 1 ◽  
High Recurrence Rate ◽  
Driver Gene ◽  
Active Growth ◽  
Disability Rate ◽  
Atypical Meningiomas

Abstract OBJECTIVE Refractory meningioma faces the problems of low total resection rate, high recurrence rate and high disability rate. Here we report a patient with recurrent refractory meningioma who was benefited from precision treatment plan based on molecular diagnosis. METHODS Molecular diagnosis by next generation sequencing (NGS) test was used to test the hybridized captured DNA in the tumor tissue of the patient. RESULTS The 53-year-old female diagnosed with meningioma was admitted to our hospital after tumor progression was observed for 3 weeks. She had received 4 operations for the tumor previously. The first three times of postoperative pathology indicated WHO Ⅰ grade meningioma. The fourth postoperative pathology showed excessive meningioma, with active growth of tumor cells in some areas and small focal necrosis, WHO Ⅰ- fair grade. Somatic mutation GNAS p.F309VFS *25 and deletion of the short arm of chromosome 1 / long arm of chromosome 22 were also found (1P / 22Q) by NGS test. The second recurrent foci showed partial amplification of 17q and 19, except for 1p/22q deletions, compared with the first. Meningiomas with 1p/22q deletion are type C meningiomas (more than half are grade WHO Ⅰ). Meningiomas have been shown to be highly vascularized neoplasms, with a 2-fold increase in VEGF expression in atypical meningiomas and a 10-fold increase in malignant meningiomas. According to the molecular diagnosis results, the precise treatment plan was determined: concurrent chemoradiotherapy, followed by anti-VEGF-targeted drugs combined with temozolomide for 2 months. The residual lesions were significantly reduced after treatment. CONCLUSION This case is the first to report a meningioma with pituitary tumor driver gene GNAS mutation, which is more prone to recurrence due to the combination of 1P / 22Q chromosome mutation. Molecular diagnosis can guide precise treatment to benefit patients.

scholarly journals Mitochondrial perturbation reduces susceptibility to xenobiotics through altered efflux in Candida albicans

Genetics ◽  
2021 ◽  
Author(s):  
Saif Hossain ◽  
Amanda O Veri ◽  
Zhongle Liu ◽  
Kali R Iyer ◽  
Teresa R O’Meara ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Mitochondrial Function ◽  
Efflux Pump ◽  
Systemic Disease ◽  
Filamentous Growth ◽  
Hsp90 Inhibitor ◽  
Homozygous Deletion ◽  
Hsp90 Inhibitors ◽  
Hsp90 Inhibition ◽  
Conditional Expression

Abstract Candida albicans is a leading human fungal pathogen, which can cause superficial infections or life-threatening systemic disease in immunocompromised individuals. The ability to transition between yeast and filamentous forms is a major virulence trait of C. albicans, and a key regulator of this morphogenetic transition is the molecular chaperone Hsp90. To explore the mechanisms governing C. albicans morphogenesis in response to Hsp90 inhibition, we performed a functional genomic screen using the gene replacement and conditional expression (GRACE) collection to identify mutants that are defective in filamentation in response to the Hsp90 inhibitor, geldanamycin. We found that transcriptional repression of genes involved in mitochondrial function blocked filamentous growth in response to the concentration of Hsp90 inhibitor used in the screen, and this was attributable to increased resistance to the compound. Further exploration revealed that perturbation of mitochondrial function reduced susceptibility to two structurally distinct Hsp90 inhibitors, geldanamycin and radicicol, such that filamentous growth was restored in the mitochondrial mutants by increasing the compound concentration. Deletion of two representative mitochondrial genes, MSU1 and SHY1, enhanced cellular efflux and reduced susceptibility to diverse intracellularly acting compounds. Additionally, screening a C. albicans efflux pump gene deletion library implicated Yor1 in efflux of geldanamycin and Cdr1, in efflux of radicicol. Deletion of these transporter genes restored sensitivity to Hsp90 inhibitors in MSU1 and SHY1 homozygous deletion mutants, thereby enabling filamentation. Taken together, our findings suggest that mitochondrial dysregulation elevates cellular efflux and consequently reduces susceptibility to xenobiotics in C. albicans.

scholarly journals Is there any Effect of Blood Glucose Level on Finger Biting?

2019 ◽  
Vol 2 (1) ◽  
Author(s):  
Hira Naeem Qureshi
Keyword(s):  
Blood Glucose ◽  
Blood Glucose Level ◽  
Glucose Level ◽  
High Glucose ◽  
Normal Glucose ◽  
Normal Glucose Level ◽  
Low Glucose ◽  
Glucose Meter ◽  
High Glucose Level

To interact glucose level of blood with finger biting was the goal of present research. 130 subjects took part in present research, where their glucose level of blood calculated. The normal glucose level in blood is in between 100 to 140mg/dl. The hyperglycemia is known as high glucose level while hypoglycemia is known as low glucose level. The biting of fingers in the mouth with teeth is known as finger biting. It also refer as onychophagia. There were 130 students take part in this research and they measured their sugar level by using glucose meter. Then they correlate the glucose level with finger biting. It was concluded from the present study that glucose level of blood has no impact on finger biting.

scholarly journals Selective Microautophagy of Proteasomes is Initiated by ESCRT-0 and Is Promoted by Proteasome Ubiquitylation

2021 ◽  
Author(s):  
Jianhui Li ◽  
Mark Hochstrasser
Keyword(s):  
Ubiquitin Ligase ◽  
Normal Growth ◽  
Ubiquitin Proteasome System ◽  
Growth Conditions ◽  
Endosomal Sorting ◽  
Glucose Depletion ◽  
Ubiquitin Binding ◽  
Ubiquitin Proteasome ◽  
Low Glucose ◽  
Amp Activated Protein Kinase

The proteasome is central to proteolysis by the ubiquitin-proteasome system under normal growth conditions but is itself degraded through macroautophagy under nutrient stress. A recently described AMPK (AMP-activated protein kinase)-regulated ESCRT (endosomal sorting complex required for transport)-dependent microautophagy pathway also regulates proteasome trafficking and degradation in low glucose conditions in yeast. Aberrant proteasomes are more prone to microautophagy, suggesting the ESCRT system fine-tunes proteasome quality control under low glucose stress. Here we uncover additional features of the selective microautophagy of proteasomes. Genetic or pharmacological induction of aberrant proteasomes is associated with increased mono- or oligo-ubiquitylation of proteasome components, which appear to be recognized by ESCRT-0. AMPK controls this pathway in part by regulating the trafficking of ESCRT-0 to the vacuole surface, which also leads to degradation of the Vps27 subunit of ESCRT-0. The Rsp5 ubiquitin ligase contributes to proteasome subunit ubiquitylation, and multiple ubiquitin-binding elements in Vps27 are involved in their recognition. We propose that ESCRT-0 at the vacuole surface recognizes ubiquitylated proteasomes and initiates their microautophagic elimination during glucose depletion.

scholarly journals Sleeping ribosomes: bacterial signaling triggers RaiA mediated persistence to aminoglycosides

2020 ◽  
Author(s):  
Manon Lang ◽  
Evelyne Krin ◽  
Chloé Korlowski ◽  
Odile Sismeiro ◽  
Hugo Varet ◽  
...  
Keyword(s):  
Sucrose Gradient ◽  
Gradient Analysis ◽  
Cell Formation ◽  
Fold Increase ◽  
Growth Conditions ◽  
Lag Phase ◽  
Bacterial Signaling ◽  
Tryptophan Degradation ◽  
70S Ribosome ◽  
Persistent Cell

AbstractIndole is a small molecule derived from tryptophan degradation and proposed to be involved in bacterial signaling. We find that indole secretion is induced by sublethal tobramycin concentrations and increases persistence to aminoglycosides in V. cholerae. Indole transcriptomics showed strongly increased expression of raiA, a ribosome associated factor. Deletion of raiA abolishes the appearance of indole dependent persisters to aminoglycosides, while its overexpression leads to 100-fold increase of persisters, and a reduction in lag phase, evocative of increased active 70S ribosome content, which was confirmed by sucrose gradient analysis. We propose that, under stress conditions, inactive 70S ribosomes are associated with RaiA to be stored and rapidly reactivated when growth conditions become favorable again, in a mechanism different than ribosome hibernation. Our results point to an active process of persistent cell formation, through ribosome protection during translational stress and relief upon antibiotic removal. Translation is a universal process, and these results could help elucidate a mechanism of persistence formation in a controlled, thus inducible way.

scholarly journals Optimized Nile Red Efflux Assay of AcrAB-TolC Multidrug Efflux System Shows Competition between Substrates

2010 ◽  
Vol 54 (9) ◽  
pp. 3770-3775 ◽  
Author(s):  
Jürgen A. Bohnert ◽  
Brian Karamian ◽  
Hiroshi Nikaido
Keyword(s):  
Antimicrobial Agents ◽  
Efflux Pump ◽  
Nile Red ◽  
Proton Conductor ◽  
Multidrug Efflux ◽  
Pump System ◽  
Tetraphenylphosphonium Chloride ◽  
Carbonyl Cyanide ◽  
Efflux Pump Inhibitors ◽  
Multidrug Efflux System

ABSTRACT AcrAB-TolC is the major constitutively expressed efflux pump system that provides resistance to a variety of antimicrobial agents and dyes in Escherichia coli. However, no systematically optimized real-time dye efflux assay has been published for the measurement of its activity and for detection of possible competition between substrates. Here, we report on the development of such an assay using a lipophilic dye, Nile Red. Energy-depleted cells were loaded with the dye in the presence of low (10 μM or less) concentrations of the proton conductor carbonyl cyanide m-chlorophenylhydrazone (CCCP). The CCCP was then removed, and efflux was triggered by energization with glucose. Various known efflux pump inhibitors and antimicrobials were checked for the ability to slow down Nile Red efflux, presumably through competition. Besides the known inhibitors Phe-Arg-β-naphthylamide and 1-naphthyl-methylpiperazine, several tetracyclic compounds (doxorubicin, minocycline, chlortetracycline, doxycycline, and tetracycline) and tetraphenylphosphonium chloride were found to interfere with dye efflux. This inhibition could not be explained by the depletion of proton motive force. None of the other tested antimicrobials, including macrolides, fluoroquinolones, and β-lactams, had any impact on Nile Red efflux, even at concentrations of up to 1 mM.

scholarly journals Transcriptional Profiling Analysis of the Global Regulator NorG, a GntR-Like Protein of Staphylococcus aureus

2011 ◽  
Vol 193 (22) ◽  
pp. 6207-6214 ◽  
Author(s):  
Q. C. Truong-Bolduc ◽  
P. M. Dunman ◽  
T. Eidem ◽  
D. C. Hooper
Keyword(s):  
Staphylococcus Aureus ◽  
Target Genes ◽  
Efflux Pump ◽  
Transcriptional Profiling ◽  
Fold Increase ◽  
Regulatory Function ◽  
Drug Transporter ◽  
Content Type ◽  
Global Regulators ◽  
Inorganic Ion

The GntR-like protein NorG has been shown to affectStaphylococcus aureusgenes involved in resistance to quinolones and β-lactams, such as those encoding the NorB and AbcA transporters. To identify the target genes regulated by NorG, we carried out transcriptional-profiling assays usingS. aureusRN6390 and its isogenicnorG::catmutant. Our data showed that NorG positively affected the transcription of global regulatorsmgrA,arlS, andsarZ. The three putative drug efflux pump genes most positively affected by NorG were the NorB efflux pump (5.1-fold), the MmpL-like protein SACOL2566 (5.2-fold), and the BcrA-like drug transporter SACOL2525 (5.7-fold) genes. TheS. aureuspredicted MmpL protein showed 53% homology with the MmpL lipid transporter ofMycobacterium tuberculosis, and the putative SACOL2525 protein showed 87% homology with the bacitracin drug transporter BcrA ofStaphylococcus hominis. Two pump genes most negatively affected by NorG were the NorC (4-fold) and AbcA (6-fold) genes. Other categories of genes, such as those participating in amino acid, inorganic ion, or nucleotide transporters and metabolism, were also affected by NorG. Real-time reverse transcription (RT)-PCR assays formgrA,arlS,sarZ,norB,norC,abcA,mmpL, andbcrA-like were carried out to verify microarray data and showed the same level of up- or downregulation by NorG. ThenorGmutant showed a 2-fold increase in resistance to norfloxacin and rhodamine, both substrates of the NorC transporter, which is consistent with the resistance phenotype conferred by overexpression ofnorCon a plasmid. These data indicate that NorG has broad regulatory function inS. aureus.

Regulation of the utilization of mRNA for eucaryotic elongation factor Tu in Friend erythroleukemia cells

1987 ◽  
Vol 7 (2) ◽  
pp. 687-697
Author(s):  
T R Rao ◽  
L I Slobin
Keyword(s):  
Stationary Phase ◽  
Elongation Factor ◽  
Fold Increase ◽  
Growth Conditions ◽  
Fresh Medium ◽  
Initiation Factor ◽  
Elongation Factor Tu ◽  
Erythroleukemia Cells ◽  
Friend Erythroleukemia Cells

When Friend erythroleukemia cells were allowed to grow to stationary phase (2 X 10(6) to 3 X 10(6) cells per ml), approximately 60% of the mRNA for eucaryotic elongation factor Tu (eEF-Tu) sedimented at less than or equal to 80S, and most of the remaining factor mRNA was associated with small polysomes. Under the same growth conditions, greater than 90% of the mRNA for eucaryotic initiation factor 4A remained associated with polysomes. The association of eEF-Tu mRNA with polysomes changed dramatically when stationary-phase cells were treated with fresh medium. After 1 h in fresh medium, approximately 90% of eEF-Tu mRNA in Friend cells was found in heavy polysomes. Associated with the shift of eEF-Tu mRNA into heavy polysomes, we found at least a 2.6-fold increase in the synthesis of eEF-Tu in vivo as well as a remarkable 40% decrease in the total amount of eEF-Tu mRNA per cell. Our data raise the possibility that eEF-Tu mRNA that has accumulated in ribonucleoprotein particles in stationary-phase cells is degraded rather than reutilized for eEF-Tu synthesis.

Effects of glucose on hypoxic vasoconstriction in isolated ferret lungs

1991 ◽  
Vol 70 (1) ◽  
pp. 439-446 ◽  
Author(s):  
C. M. Wiener ◽  
J. T. Sylvester
Keyword(s):  
High Glucose ◽  
Early Phase ◽  
Continuous Measurement ◽  
Late Phase ◽  
Vascular Response ◽  
Vasomotor Responses ◽  
Hypoxic Vasoconstriction ◽  
Normal Glucose ◽  
Low Glucose ◽  
Pulmonary Arterial

To characterize the effects of glucose on the pulmonary vascular response to anoxia and hypoxia, isolated ferret lungs were ventilated with 28% O2 and 5% CO2 and perfused at constant flow (100 ml.kg-1.min-1). Perfusate glucose concentrations were allowed to fall spontaneously to less than 1 mM (low glucose) or were controlled at 5–6 mM (normal glucose) or 12–17 mM (high glucose). At 60, 120, and 180 min of perfusion, the inspired O2 tension (PIO2) was reduced to 0, 10, or 30 Torr for 30 min, and vasomotor responses were quantified by continuous measurement of pulmonary arterial pressure. At PIO2 of 0 Torr, the response consisted of an early phase of transient intense vasoconstriction and a late phase of sustained slight vasoconstriction. High glucose markedly potentiated the magnitude of late-phase vasoconstriction with each successive anoxic exposure. This effect was not reproduced in normal glucose lungs and was not caused by a change in perfusate osmolarity, an action on blood cells, or an altered ability of pulmonary vascular smooth muscle to contract. At PIO2 of 10 Torr, high glucose not only potentiated late-phase vasoconstriction but also slowed the onset of early-phase vasoconstriction. At PIO2 of 30 Torr, high glucose had no effect on vasomotor responses, which were characterized by a slowly developing sustained vasoconstriction. Our results suggest that the vascular response of isolated ferret lungs to severe hypoxia consisted of separate early and late phases of vasoconstriction. This biphasic response may have resulted from two distinct vasoconstrictor mechanisms or from modulation of a single vasoconstrictor mechanism by a secondary vasodilator influence.(ABSTRACT TRUNCATED AT 250 WORDS)

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