Diet-induced changes in titer support a threshold effect of Wolbachia-associated plastic recombination in Drosophila melanogaster

Mapping Intimacies ◽

10.1101/2021.03.18.436076 ◽

2021 ◽

Author(s):

Sabrina L Mostoufi ◽

Nadia D Singh

Keyword(s):

Drosophila Melanogaster ◽

Wolbachia Infection ◽

Threshold Effect ◽

Bacterial Concentration ◽

Wolbachia Pipientis ◽

Intrinsic Factors ◽

Induced Changes ◽

And Control ◽

Dose Dependent ◽

Extrinsic And Intrinsic Factors

Plastic recombination in Drosophila melanogaster has been associated with a variety of extrinsic and intrinsic factors such as temperature, starvation, and parasite infection. The bacterial endosymbiont Wolbachia pipientis has also been associated with plastic recombination in D. melanogaster. Wolbachia infection is pervasive in arthropods and this infection induces a variety of phenotypes in its hosts, the strength of which can depend on bacterial concentration, or titer. Here we test the hypothesis that the magnitude of Wolbachia-associated plastic recombination in D. melanogaster depends on titer. To manipulate titer, we raised Wolbachia-infected and uninfected flies on diets that have previously been shown to increase or decrease Wolbachia titer relative to controls. We measured recombination in treated and control individuals using a standard backcrossing scheme with two X-linked visible markers. Our results recapitulate previous findings that Wolbachia infection is associated with increased recombination rate across the yellow-vermillion interval of the X chromosome. Our data show no significant effect of diet or diet by Wolbachia interactions on recombination, suggesting that diet-induced changes in Wolbachia titer have no effect on the magnitude of plastic recombination. These findings represent the first step toward investigating the mechanisms behind Wolbachia-associated plastic recombination and demonstrate that the effect may be threshold-based as opposed to dose-dependent.

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Diet-induced changes in titer support a discrete response of Wolbachia-associated plastic recombination in Drosophila melanogaster

G3 Genes|Genome|Genetics ◽

10.1093/g3journal/jkab375 ◽

2021 ◽

Author(s):

Sabrina L Mostoufi ◽

Nadia D Singh

Keyword(s):

Drosophila Melanogaster ◽

Wolbachia Infection ◽

Parasite Infection ◽

Wolbachia Pipientis ◽

Intrinsic Factors ◽

Bacterial Titer ◽

Discrete Response ◽

Induced Changes ◽

And Control ◽

Extrinsic And Intrinsic Factors

Abstract Plastic recombination in Drosophila melanogaster has been associated with a variety of extrinsic and intrinsic factors such as temperature, starvation, and parasite infection. The bacterial endosymbiont Wolbachia pipientis has also been associated with plastic recombination in D. melanogaster. Wolbachia infection is pervasive in arthropods and this infection induces a variety of phenotypes in its hosts, the strength of which can depend on bacterial titer. Here we test the hypothesis that the magnitude of Wolbachia-associated plastic recombination in D. melanogaster depends on titer. To manipulate titer, we raised Wolbachia-infected and uninfected flies on diets that have previously been shown to increase or decrease Wolbachia titer relative to controls. We measured recombination in treated and control individuals using a standard backcrossing scheme with two X-linked visible markers. Our results recapitulate previous findings that Wolbachia infection is associated with increased recombination rate across the yellow-vermillion interval of the X chromosome. Our data show no significant effect of diet or diet by Wolbachia interactions on recombination, suggesting that diet-induced changes in Wolbachia titer have no effect on the magnitude of plastic recombination. These findings represent one of the first steps toward investigating Wolbachia-associated plastic recombination and demonstrate that the phenotype is a discrete response rather than a continuous one.

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

Insects ◽

10.3390/insects11050284 ◽

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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Recirculation versus flow-through rainbow trout laboratory Flavobacterium columnare challenge

Diseases of Aquatic Organisms ◽

10.3354/dao03487 ◽

2020 ◽

Vol 139 ◽

pp. 213-221

Author(s):

C Birkett ◽

R Lipscomb ◽

T Moreland ◽

T Leeds ◽

JP Evenhuis

Keyword(s):

Rainbow Trout ◽

Environmental Parameters ◽

Cumulative Effects ◽

Flavobacterium Columnare ◽

Replacement Rate ◽

Bacterial Concentration ◽

Water Replacement ◽

Dose Concentration ◽

Flow Through ◽

And Control

Flavobacterium columnare immersion challenges are affected by water-related environmental parameters and thus are difficult to reproduce. Whereas these challenges are typically conducted using flow-through systems, use of a recirculating challenge system to control environmental parameters may improve reproducibility. We compared mortality, bacterial concentration, and environmental parameters between flow-through and recirculating immersion challenge systems under laboratory conditions using 20 rainbow trout families. Despite identical dose concentration (1:75 dilution), duration of challenge, lot of fish, and temperature, average mortality in the recirculating system (42%) was lower (p < 0.01) compared to the flow-through system (77%), and there was low correlation (r = 0.24) of family mortality. Mean days to death (3.25 vs. 2.99 d) and aquaria-to-aquaria variation (9.6 vs. 10.4%) in the recirculating and flow-through systems, respectively, did not differ (p ≥ 0.30). Despite 10-fold lower water replacement rate in the recirculating (0.4 exchanges h-1) compared to flow-through system (4 exchanges h-1), differences in bacterial concentration between the 2 systems were modest (≤0.6 orders of magnitude) and inconsistent throughout the 21 d challenge. Compared to the flow-through system, dissolved oxygen during the 1 h exposure and pH were greater (p ≤ 0.02), and calcium and hardness were lower (p ≤ 0.03), in the recirculating system. Although this study was not designed to test effects of specific environmental parameters on mortality, it demonstrates that the cumulative effects of these parameters result in poor reproducibility. A recirculating immersion challenge model may be warranted to empirically identify and control environmental parameters affecting mortality and thus may serve as a more repeatable laboratory challenge model.

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Генотип эндосимбионта Wolbachia pipientis влияет на метаболизм октопамина у самок Drosophila melanogaster

Генетика ◽

10.1134/s0016675819050023 ◽

2019 ◽

Vol 55 (5) ◽

pp. 609-612

Author(s):

Н. В. Адоньева ◽

Е. В. Бурдина ◽

Р. А. Быков ◽

Н. Е. Грунтенко ◽

И. Ю. Раушенбах

Keyword(s):

Drosophila Melanogaster ◽

Wolbachia Pipientis

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The genetics of catalase in Drosophila melanogaster: isolation and characterization of acatalasemic mutants.

Genetics ◽

10.1093/genetics/122.3.643 ◽

1989 ◽

Vol 122 (3) ◽

pp. 643-652 ◽

Cited By ~ 1

Author(s):

W J Mackay ◽

G C Bewley

Keyword(s):

Drosophila Melanogaster ◽

Free Radical ◽

Catalase Activity ◽

Oxygen Toxicity ◽

Threshold Effect ◽

Culture Conditions ◽

Free Radical Damage ◽

Isolation And Characterization ◽

Standard Culture ◽

Hypomorphic Alleles

Abstract Activated oxygen species have been demonstrated to be the important agents in oxygen toxicity by disrupting the structural and functional integrity of cells through lipid peroxidation events, DNA damage and protein inactivation. The biological consequences of free radical damage have long been hypothesized to be a causal agent in many aging-related diseases. Catalase (H2O2:H2O2 oxidoreductase; EC 1.15.1.1) is one of several enzymes involved in the scavenging of oxygen free radicals and free radical derivatives. The structural gene for catalase in Drosophila melanogaster has been localized to region 75D1-76A on chromosome 3L by dosage responses to segmental aneuploidy. This study reports the isolation of a stable deficiency, Df(3L)CatDH104(75C1-2;75F1), that uncovers the catalase locus and the subsequent isolation of six acatalasemic mutants. All catalase mutants are viable under standard culture conditions and recessive lethal mutations within the 75Cl-F1 interval have been shown not to affect catalase activity. Two catalase mutations are amorphic while four are hypomorphic alleles of the Cat+ locus. The lack of intergenic complementation between the six catalase mutations strongly suggests that there is only one functional gene in Drosophila. One acatalesemic mutation was mapped to position 3-47.0 which resides within the catalase dosage sensitive region. While complete loss of catalase activity confers a severe viability effect, residual levels are sufficient to restore viability to wild type levels. These results suggest a threshold effect for viability and offer an explanation for the general lack of phenotypic effects associated with the known mammalian acatalasemics.

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The Anti-Ageing and Whitening Potential of a Cosmetic Serum Containing 3-O-ethyl-l-ascorbic Acid

Life ◽

10.3390/life11050406 ◽

2021 ◽

Vol 11 (5) ◽

pp. 406

Author(s):

Nicola Zerbinati ◽

Sabrina Sommatis ◽

Cristina Maccario ◽

Serena Di Francesco ◽

Maria Chiara Capillo ◽

...

Keyword(s):

Ascorbic Acid ◽

Dermal Fibroblasts ◽

Melanin Content ◽

Dna Protection ◽

Melanin Pigmentation ◽

Intrinsic Factors ◽

Reconstructed Human Epidermis ◽

Solar Ultraviolet ◽

Damage Marker ◽

Extrinsic And Intrinsic Factors

Skin ageing has many manifestations such as wrinkles, dryness, hyperpigmentation, and uneven skin tone. Extrinsic and intrinsic factors, especially solar ultraviolet light (UVB), contribute to skin ageing; its main features are brown spots, alterations in melanin pigmentation, and a decrease in collagen and hyaluronic acid linked to oxidative stress. Several studies showed that topical products containing ingredients with antioxidant activity can reduce oxidative damage; to provide a maximum anti-ageing effect to the skin, topical products can combine various ingredients. C-SHOT SERUM contains a combination of two molecules with a proven anti-ageing activity: a high percentage (30%) of a more stable vitamin C derivative, 3-O-ethyl-l-ascorbic acid, and lactic acid (1%). The product showed a high biocompatibility, assessed through an MTT assay on keratinocytes and on Reconstructed Human Epidermis (RHE, SkinEthic); the anti-ageing activity was demonstrated on human dermal fibroblasts and keratinocytes by a statistically significant increase in collagen production and a reduction of a UVB-induced DNA damage marker (γ-H2AX histone), indicating DNA protection. Moreover, a depigmenting activity, shown by a highly significant decrease in melanin content on treated Reconstructed Human Pigmented Epidermis (RHPE), was assessed. According to the data of our study, the tested product contrasts the effect of skin ageing and irregular pigmentation due to the physiological decline of the skin.

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Cytotoxic Effects of N,N-Diethyl-Meta-Toluamide (DEET) on Sinonasal Epithelia

OTO Open ◽

10.1177/2473974x211009232 ◽

2021 ◽

Vol 5 (2) ◽

pp. 2473974X2110092

Author(s):

Jivianne T. Lee ◽

Saroj Basak

Keyword(s):

Cell Viability ◽

Chronic Rhinosinusitis ◽

Morphological Changes ◽

Environmental Toxicants ◽

Cytotoxic Effects ◽

Airborne Pollutants ◽

Cell Monitoring ◽

History Of ◽

And Control ◽

Dose Dependent

Although the etiology of chronic rhinosinusitis remains unknown, environmental factors including airborne pollutants and toxicants are postulated to contribute to its pathogenesis. However, the precise pathomechanisms with which environmental toxicants may contribute to chronic rhinosinusitis are not fully understood. The purpose of this pilot study is to examine the cytotoxic effects of N,N-diethyl- meta-toluamide (DEET), a commonly used pesticide, on sinonasal epithelial cells (SNECs). Sinus mucosa was obtained from 3 subjects without a history of chronic rhinosinusitis. Cultured SNECs were exposed to various concentrations of DEET (0-5 mM) for 6 days. Cell viability, proliferation, and morphologic changes were assessed using the MTT colorimetric dye assay and the Incucyte Live Cell Monitoring System. Statistically significant dose-dependent reduction in cell viability and proliferation was observed between exposure and control groups ( P < .05) at all concentrations tested. Dose-dependent cellular morphological changes were also seen. These findings indicate that DEET exposure induces dose-dependent cytotoxicity in sinonasal epithelia.

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The economic value and determinants of tourists’ counterfeit purchases: The case of Hong Kong

Tourism Economics ◽

10.1177/1354816619834482 ◽

2019 ◽

Vol 26 (1) ◽

pp. 155-178 ◽

Cited By ~ 3

Author(s):

Stephen Pratt ◽

Christine YH Zeng

Keyword(s):

Hong Kong ◽

Brand Image ◽

Economic Value ◽

Demand Side ◽

Counterfeit Goods ◽

Intrinsic Factors ◽

Extrinsic And Intrinsic Factors

Counterfeiting of fashion brands is a multi-billion dollar industry with an increasing number of goods being counterfeited. This research takes a demand-side approach to measuring counterfeiting activity among tourists in Hong Kong. Non-deceptive counterfeit purchases by tourists in Hong Kong amount to US$761.32 million per year. Tourists’ decision of whether to purchase counterfeit goods depended on a mix of extrinsic and intrinsic factors including psychometric variables, trip-related characteristics, and sociodemographics. Lowering the prices of genuine goods and explaining the risks of purchasing counterfeit goods would be the most effective anti-counterfeit measures. However, lowering the price of genuine goods can diminish the brand image of these luxury items.

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