scholarly journals Copper homoeostasis in Drosophila melanogaster S2 cells

2004 ◽  
Vol 383 (2) ◽  
pp. 303-309 ◽  
Author(s):  
Adam SOUTHON ◽  
Richard BURKE ◽  
Melanie NORGATE ◽  
Philip BATTERHAM ◽  
James CAMAKARIS
Keyword(s):  
Drosophila Melanogaster ◽  
Mammalian Cells ◽  
Copper Chaperone ◽  
Dependent Manner ◽  
S2 Cells ◽  
Gene Expressions ◽  
Drosophila Melanogaster S2 Cells ◽  
Human Orthologue ◽  
Transcription Factor 1 ◽  
Dose Dependent

Copper homoeostasis was investigated in the Drosophila melanogaster S2 cell line to develop an insect model for the study of copper regulation. Real-time PCR studies have demonstrated expression in S2 cells of putative orthologues of human Cu regulatory genes involved in the uptake, transport, sequestration and efflux of Cu. Drosophila orthologues of the mammalian Cu chaperones, ATOX1 (a human orthologue of yeast ATX1), CCS (copper chaperone for superoxide dismutase), COX17 (a human orthologue of yeast COX17), and SCO1 and SCO2, did not significantly respond transcriptionally to increased Cu levels, whereas MtnA, MtnB and MtnD (Drosophila orthologues of human metallothioneins) were up-regulated by Cu in a time- and dose-dependent manner. To examine the effect on Cu homoeostasis, expression of several key copper homoeostasis genes was suppressed using double-stranded RNA interference. Suppression of the MTF-1 (metal-regulatory transcription factor 1), reduced both basal and Cu-induced gene expressions of MtnA, MtnB and MtnD, significantly reducing the tolerance of these cells to increased Cu. Suppression of either Ctr1A (a Drosophila orthologue of yeast CTR1) or Ctr1B significantly reduced Cu uptake from media, demonstrating that both these proteins function to transport Cu into S2 cells. Significantly, Cu induced Ctr1B gene expression, and this could be prevented by suppressing MTF-1, suggesting that Ctr1B might be involved in Cu detoxification. Suppression of DmATP7, the putative homologue of human Cu transporter genes ATP7A and ATP7B, significantly increased Cu accumulation, demonstrating that DmATP7 is essential for efflux of excess Cu. This work is consistent with previous studies in mammalian cells, validating S2 cells as a model system for studying Cu transport and identifying novel Cu regulatory mechanisms.

scholarly journals Antifungal activity of dendritic cell lysosomal proteins against Cryptococcus neoformans

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Benjamin N. Nelson ◽  
Savannah G. Beakley ◽  
Sierra Posey ◽  
Brittney Conn ◽  
Emma Maritz ◽  
...  
Keyword(s):  
Antifungal Activity ◽  
Cryptococcus Neoformans ◽  
Mammalian Cells ◽  
Cysteine Proteases ◽  
Dependent Manner ◽  
Life Threatening ◽  
Opportunistic Fungal Pathogen ◽  
Dose Dependent ◽  
Lysosomal Proteins

AbstractCryptococcal meningitis is a life-threatening disease among immune compromised individuals that is caused by the opportunistic fungal pathogen Cryptococcus neoformans. Previous studies have shown that the fungus is phagocytosed by dendritic cells (DCs) and trafficked to the lysosome where it is killed by both oxidative and non-oxidative mechanisms. While certain molecules from the lysosome are known to kill or inhibit the growth of C. neoformans, the lysosome is an organelle containing many different proteins and enzymes that are designed to degrade phagocytosed material. We hypothesized that multiple lysosomal components, including cysteine proteases and antimicrobial peptides, could inhibit the growth of C. neoformans. Our study identified the contents of the DC lysosome and examined the anti-cryptococcal properties of different proteins found within the lysosome. Results showed several DC lysosomal proteins affected the growth of C. neoformans in vitro. The proteins that killed or inhibited the fungus did so in a dose-dependent manner. Furthermore, the concentration of protein needed for cryptococcal inhibition was found to be non-cytotoxic to mammalian cells. These data show that many DC lysosomal proteins have antifungal activity and have potential as immune-based therapeutics.

The P-element-induced silencing effect of KP transposons is dose dependent in Drosophila melanogaster

Genome ◽  
2011 ◽  
Vol 54 (9) ◽  
pp. 752-762 ◽  
Author(s):  
Alireza Sameny ◽  
John Locke
Keyword(s):  
Drosophila Melanogaster ◽  
Critical Role ◽  
Mutagenic Effect ◽  
P Element ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
P Elements ◽  
Single Well ◽  
Dose Dependent

Transposable elements are found in the genomes of all eukaryotes and play a critical role in altering gene expression and genome organization. In Drosophila melanogaster, transposable P elements are responsible for the phenomenon of hybrid dysgenesis. KP elements, a deletion-derivative of the complete P element, can suppress this mutagenic effect. KP elements can also silence the expression of certain other P-element-mediated transgenes in a process called P-element-dependent silencing (PDS), which is thought to involve the recruitment of heterochromatin proteins. To explore the mechanism of this silencing, we have mobilized KP elements to create a series of strains that contain single, well-defined KP insertions that show PDS. To understand the quantitative role of KP elements in PDS, these single inserts were combined in a series of crosses to obtain genotypes with zero, one, or two KP elements, from which we could examine the effect of KP gene dose. The extent of PDS in these genotypes was shown to be dose dependent in a logarithmic rather than linear fashion. A logarithmic dose dependency is consistent with the KP products interacting with heterochromatic proteins in a concentration-dependent manner such that two molecules are needed to induce gene silencing.

Abstract 619: Alpha Keto Acids Decompose Peroxides and Prevents Oxidation of Lipoproteins

2016 ◽  
Vol 36 (suppl_1) ◽  
Author(s):  
Chandrakala Aluganti Narasimhulu ◽  
Kathryn Young Burge ◽  
Yu Yuan ◽  
Sampath Parthasarathy
Keyword(s):  
Therapeutic Potential ◽  
Lipid Peroxides ◽  
Enzymatic Oxidation ◽  
Raw 264.7 Cells ◽  
Dependent Manner ◽  
Gene Expressions ◽  
Dual Effect ◽  
Keto Acids ◽  
Hydroperoxyoctadecadienoic Acid ◽  
Dose Dependent

Background: Alpha keto acids are unstable and decompose rapidly. In this study, we tested the ability of alpha keto acids to reduce peroxides and inhibit oxidation of lipoproteins. Methods: Keto salicylic acid (KSA) and Keto Octanoicacid (KoA) were synthesized and their ability to reduce hydrogen peroxides as well as lipid peroxides (LOOH) was measured using 13-hydroperoxyoctadecadienoic acid (13-HPODE). Lipoproteins (LDL and HDL) were isolated from human plasma and oxidation of liporproteins was performed using copper and MPO in the presence or absence of the keto compounds. RAW 264.7 cells and HUVECS were incubated with LPS and mm-LDL respectively either in the presence or absence of the keto compounds. RNA was isolated from treated cells and real time PCR was performed to analyze IL-1α, IL-6, MCP-1 and VCAM1 gene expressions. Reactive oxygen species were evaluated using DCF fluorescence in presence and absence of the keto compounds. Results: KSA reduced both H2O2 and 13-HPODE whereas KoA is able to reduce the former but not the latter. Both compounds inhibited the lipoprotein oxidation in a dose dependent manner and were able to reduce ROS production by H2O2. KSA is able to inhibit both LPS as well as mm-LDL induced inflammation. However, KoA showed a dual effect as it induced inflammatory markers in the presence of LPS, but inhibited the mm-LDL-induced inflammatory gene expressions. Conclusion: The results of our studies suggest that these keto compounds a) inhibit both enzymatic and non enzymatic oxidation of lipoproteins; b) reduce peroxides and ROS and c) have inhibitory and inducing effect on inflammatory cytokine/gene production in presence of mm-LDL and LPS respectively. Based on these results, we predict that these keto compounds could have therapeutic potential in reducing CVD/atherosclerosis-associated inflammation.

Virgin Coconut (Cocos nucifera) Oil Attenuates Rotenone-Induced Toxicity in Fruit Flies (Drosophila melanogaster)

2021 ◽  
Vol 2 (1) ◽  
pp. 26-37
Author(s):  
O.O. Dosumu ◽  
◽  
E.N. Akang ◽  
O.K. Idowu ◽  
G.J. Adeyemi
Keyword(s):  
Drosophila Melanogaster ◽  
Cocos Nucifera ◽  
Coconut Oil ◽  
Redox Status ◽  
Fruit Flies ◽  
Dependent Manner ◽  
Toxicity Assay ◽  
Behavioural Test ◽  
Locomotor Deficits ◽  
Dose Dependent

Background: Parkinson's disease (PD) is a multifactorial neurodegenerative disease with pathogenic mechanisms traceable to oxidative damage and mitochondrial dysfunction. Rotenone, a chemical compound commonly found in pesticides, has been found to inhibit mitochondrial complex-I and initiate PD-like symptoms in mammals and several invertebrates. Virgin Coconut Oil (VCNO) obtained from the coconut fruit has been found to possess anti-oxidative and anti-inflammatory properties. Objectives: The present study evaluated the effect of VCNO on rotenone-induced Parkinsonism in fruit flies- Drosophila melanogaster (D. melanogaster). Methods: Canton special (CS) strains of D. melanogaster, aged between 1 to 3 days were orally exposed for 7 days to 0, 250, 500 and 750 μM rotenone diet for toxicity assay, and 0, 2.5, 5 and 10 % w/w VCNO diet for longevity assay. Thereafter, 5 % VCNO diet was selected for evaluation against 500 μM rotenone. Subsequently, behavioural test (negative geotaxis), markers for redox status and enzyme activities were evaluated. Results: The results showed that rotenone induced toxicity in the flies, while VCNO increased the lifespan of D. melanogaster in a dose-dependent manner. In addition, VCNO ameliorated rotenone-induced locomotor deficits, elevated MDA, as well as the depleted GSH levels. It also mitigated the inhibited activities of SOD, CAT and ATPase in the flies. Conclusions: VCNO protected D. melanogaster against rotenone-induced toxicity by extending longevity, preventing locomotor deficits and reducing oxidative stress.

scholarly journals The Intracellular Symbiont Wolbachia pipientis Enhances Recombination in a Dose-Dependent Manner

Insects ◽  
2020 ◽  
Vol 11 (5) ◽  
pp. 284
Author(s):  
Kaeli N. Bryant ◽  
Irene L. G. Newton
Keyword(s):  
Drosophila Melanogaster ◽  
Horizontal Transmission ◽  
Wolbachia Infection ◽  
Wolbachia Strain ◽  
Dependent Manner ◽  
Predator Prey ◽  
Wolbachia Pipientis ◽  
Intracellular Symbiont ◽  
Dose Dependent ◽  
Classical Genetics

Wolbachia pipientis is an intracellular alphaproteobacterium that infects 40%–60% of insect species and is well known for host reproductive manipulations. Although Wolbachia are primarily maternally transmitted, evidence of horizontal transmission can be found in incongruent host–symbiont phylogenies and recent acquisitions of the same Wolbachia strain by distantly related species. Parasitoids and predator–prey interactions may indeed facilitate the transfer of Wolbachia between insect lineages, but it is likely that Wolbachia are acquired via introgression in many cases. Many hypotheses exist to explain Wolbachia prevalence and penetrance, such as nutritional supplementation, protection from parasites, protection from viruses, or direct reproductive parasitism. Using classical genetics, we show that Wolbachia increase recombination in infected lineages across two genomic intervals. This increase in recombination is titer-dependent as the wMelPop variant, which infects at higher load in Drosophila melanogaster, increases recombination 5% more than the wMel variant. In addition, we also show that Spiroplasma poulsonii, another bacterial intracellular symbiont of D. melanogaster, does not induce an increase in recombination. Our results suggest that Wolbachia infection specifically alters its host’s recombination landscape in a dose-dependent manner.

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