scholarly journals A specialist flea beetle manipulates and tolerates the activated chemical defense in its host plant

2021 ◽  
Author(s):  
Theresa Sporer ◽  
Johannes Koernig ◽  
Natalie Wielsch ◽  
Steffi Gebauer-Jung ◽  
Michael Reichelt ◽  
...  
Keyword(s):  
Flea Beetle ◽  
Negative Influence ◽  
The Body ◽  
Wild Type ◽  
Gut Content ◽  
Feeding Experiments ◽  
Sequestration Rate ◽  
Hydrolysis Of ◽  
Myrosinase Activity

Glucosinolates, the characteristic secondary metabolites of Brassicales, are hydrolyzed upon herbivory by myrosinases to toxic and deterrent defense metabolites. The specialist flea beetle, Phyllotreta armoraciae, sequesters glucosinolates in the body despite myrosinase activity, but it is unknown whether plant myrosinase activity influences sequestration and how beetles prevent the hydrolysis of ingested glucosinolates. In feeding experiments performed with the myrosinase-deficient Arabidopsis thaliana tgg1tgg2 (tgg) mutant and the corresponding wild type, we found that plant myrosinases reduced the glucosinolate sequestration rate by up to 50% and hydrolyzed a fraction of ingested glucosinolates in adult beetles. Although these results show that P. armoraciae cannot fully prevent glucosinolate hydrolysis, we observed no negative influence on beetle performance. To understand how P. armoraciae can avoid the hydrolysis of some ingested glucosinolates, we analyzed their fate directly after ingestion. P. armoraciae rapidly absorbed glucosinolates across the gut epithelium, a strategy that has been proposed to prevent hydrolysis in the gut lumen of sequestering insects. Moreover, beetle gut content suppressed in vitro myrosinase activity, and almost no myrosinase activity was detectable in the feces, which indicates that ingested myrosinases are inactivated in the beetle gut. In summary, we show that P. armoraciae uses several strategies to prevent the hydrolysis of ingested glucosinolates but can also tolerate the formation of glucosinolate hydrolysis products.

scholarly journals Hijacking the Mustard-Oil Bomb: How a Glucosinolate-Sequestering Flea Beetle Copes With Plant Myrosinases

2021 ◽  
Vol 12 ◽  
Author(s):  
Theresa Sporer ◽  
Johannes Körnig ◽  
Natalie Wielsch ◽  
Steffi Gebauer-Jung ◽  
Michael Reichelt ◽  
...  
Keyword(s):  
Flea Beetle ◽  
The Body ◽  
Mustard Oil ◽  
Short Term ◽  
Uptake Mechanism ◽  
Experimental Conditions ◽  
Feeding Experiments ◽  
Hydrolysis Products ◽  
Sequestration Rate ◽  
Myrosinase Activity

Myrosinase enzymes play a key role in the chemical defense of plants of the order Brassicales. Upon herbivory, myrosinases hydrolyze the β-S-linked glucose moiety of glucosinolates, the characteristic secondary metabolites of brassicaceous plants, which leads to the formation of different toxic hydrolysis products. The specialist flea beetle, Phyllotreta armoraciae, is capable of accumulating high levels of glucosinolates in the body and can thus at least partially avoid plant myrosinase activity. In feeding experiments with the myrosinase-deficient Arabidopsis thaliana tgg1 × tgg2 (tgg) mutant and the corresponding Arabidopsis Col-0 wild type, we investigated the influence of plant myrosinase activity on the metabolic fate of ingested glucosinolates in adult P. armoraciae beetles. Arabidopsis myrosinases hydrolyzed a fraction of ingested glucosinolates and thereby reduced the glucosinolate sequestration rate by up to 50% in adult beetles. These results show that P. armoraciae cannot fully prevent glucosinolate hydrolysis; however, the exposure of adult beetles to glucosinolate hydrolysis products had no impact on the beetle’s energy budget under our experimental conditions. To understand how P. armoraciae can partially prevent glucosinolate hydrolysis, we analyzed the short-term fate of ingested glucosinolates and found them to be rapidly absorbed from the gut. In addition, we determined the fate of ingested Arabidopsis myrosinase enzymes in P. armoraciae. Although we detected Arabidopsis myrosinase protein in the feces, we found only traces of myrosinase activity, suggesting that P. armoraciae can inactivate plant myrosinases in the gut. Based on our findings, we propose that the ability to tolerate plant myrosinase activity and a fast glucosinolate uptake mechanism represent key adaptations of P. armoraciae to their brassicaceous host plants.

scholarly journals Angiogenic Deficiency and Adipose Tissue Dysfunction Are Associated with Macrophage Malfunction in SIRT1−/− Mice

Endocrinology ◽  
2012 ◽  
Vol 153 (4) ◽  
pp. 1706-1716 ◽  
Author(s):  
Fen Xu ◽  
David Burk ◽  
Zhanguo Gao ◽  
Jun Yin ◽  
Xia Zhang ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Adipocyte Differentiation ◽  
Nuclear Factor Κb ◽  
The Body ◽  
Sirtuin 1 ◽  
Vascular Density ◽  
Peroxisome Proliferator ◽  
Wild Type ◽  
Peroxisome Proliferator Activated Receptor

The histone deacetylase sirtuin 1 (SIRT1) inhibits adipocyte differentiation and suppresses inflammation by targeting the transcription factors peroxisome proliferator-activated receptor γ and nuclear factor κB. Although this suggests that adiposity and inflammation should be enhanced when SIRT1 activity is inactivated in the body, this hypothesis has not been tested in SIRT1 null (SIRT1−/−) mice. In this study, we addressed this issue by investigating the adipose tissue in SIRT1−/− mice. Compared with their wild-type littermates, SIRT1 null mice exhibited a significant reduction in body weight. In adipose tissue, the average size of adipocytes was smaller, the content of extracellular matrix was lower, adiponectin and leptin were expressed at 60% of normal level, and adipocyte differentiation was reduced. All of these changes were observed with a 50% reduction in capillary density that was determined using a three-dimensional imaging technique. Except for vascular endothelial growth factor, the expression of several angiogenic factors (Pdgf, Hgf, endothelin, apelin, and Tgf-β) was reduced by about 50%. Macrophage infiltration and inflammatory cytokine expression were 70% less in the adipose tissue of null mice and macrophage differentiation was significantly inhibited in SIRT1−/− mouse embryonic fibroblasts in vitro. In wild-type mice, macrophage deletion led to a reduction in vascular density. These data suggest that SIRT1 controls adipose tissue function through regulation of angiogenesis, whose deficiency is associated with macrophage malfunction in SIRT1−/− mice. The study supports the concept that inflammation regulates angiogenesis in the adipose tissue.

scholarly journals Epoxide hydrolase 3 (Ephx3) gene disruption reduces ceramide linoleate epoxide hydrolysis and impairs skin barrier function

2020 ◽  
pp. jbc.RA120.016570
Author(s):  
Matthew L. Edin ◽  
Haruto Yamanashi ◽  
William E. Boeglin ◽  
Joan P. Graves ◽  
Laura M. DeGraff ◽  
...  
Keyword(s):  
Epoxide Hydrolase ◽  
Skin Barrier ◽  
Skin Barrier Function ◽  
Potential Contribution ◽  
Wild Type ◽  
Lipoxygenase Pathway ◽  
Physiological Relevance ◽  
Hydrolysis Of

The mammalian epoxide hydrolase EPHX3 is known from in vitro experiments to efficiently hydrolyze the linoleate epoxides 9,10-epoxyoctadecamonoenoic acid (EpOME) and epoxyalcohol 9R,10R-trans-epoxy-11E-13R-hydroxy-octadecenoate to corresponding diols and triols, respectively. Herein we examined the physiological relevance of EPHX3 to hydrolysis of both substrates in vivo.  Ephx3-/- mice show no deficiency in EpOME-derived plasma diols, discounting a role for EPHX3 in their formation, whereas epoxyalcohol-derived triols esterified in acylceramides of the epidermal 12R-lipoxygenase pathway are reduced. Although the Ephx3-/- pups appear normal, measurements of trans-epidermal water loss detected a modest and statistically significant increase compared to the wild-type or heterozygote mice, reflecting a skin barrier impairment that was not evident in the knockouts of mouse microsomal epoxide hydrolase (EPHX1/mEH) or soluble epoxide hydrolase (EPHX2/sEH). This barrier phenotype in the Ephx3-/- pups was associated with a significant decrease in the covalently bound ceramides in the epidermis (40% reduction, p<0.05), indicating a corresponding structural impairment in the integrity of the water barrier. Quantitative LC-MS analysis of the esterified linoleate-derived triols in the murine epidermis revealed a marked and isomer-specific reduction (~85%) in the Ephx3-/- epidermis of the major trihydroxy isomer 9R,10S,13R-trihydroxy-11E-octadecenoate. We conclude EPHX3 (and not EPHX1 or EPHX2) catalyzes hydrolysis of the 12R-LOX/eLOX3-derived epoxyalcohol esterified in acylceramide, and may function to control flux through the alternative and crucial route of metabolism via the dehydrogenation pathway of SDR9C7. Importantly, our findings also identify a functional role for EPHX3 in transformation of a naturally esterified epoxide substrate, pointing to its potential contribution in other tissues.

Dynamics of the Tissue-Specific Metabolism of Luteolin Glucuronides in the Mesophyll of Rye Primary Leaves (Secale cereale)

1988 ◽  
Vol 43 (3-4) ◽  
pp. 187-193 ◽  
Author(s):  
Margot Schulz ◽  
Gottfried Weissenböck
Keyword(s):  
Cinnamic Acid ◽  
Secale Cereale ◽  
Leaf Development ◽  
Glucuronic Acid ◽  
Developmental Stages ◽  
Leaf Tissue ◽  
Feeding Experiments ◽  
Secale Cereale L ◽  
Hydrolysis Of

Developing primary leaves of Secale cereale L. exhibit a dynamic metabolism of the major flavonoid luteolin 7-O-[β-ᴅ-glucuronosyl(1→2)β-ᴅ-glucuronide]-4′-O-β-ᴅ-glucuronide (R1). Final steps of R, biosynthesis are sequential glucuronidations of luteolin, which are catalyzed by three specific UDP-glucuronate: flavone glucuronosyltransferases. These enzymes reach highest activities at the fourth and fifth day of leaf development, coinciding with maximal R, accumulation. The activities decrease with advancing age of the leaves. In contrast, a R1-specific β-glucuronidase, responsible for the hydrolysis of glucuronic acid in position 4′, shows increasing activity up to the 5th or 6th day; but this activity, leading to luteolin 7-O-diglucuronide (R2), is not reduced in later developmental stages. In this phase of leaf development, the amount of R, drastically drops, whereas R2 accumulates only slightly. From in vitro results and from feeding experiments using [14C]cinnamic acid, a precursor of R, biosynthesis, we conclude that the anabolic sequential glucuronidation takes place in young and expanding leaf tissue, whereas deglucuronidation occurs in nearly mature and mature tissue. The three glucuronosyltransferases as well as the β-glucuronidase, and the flavonoids R1 and R2 are localized in the mesophyll.

In Reply: Erythromycin in the Middle Ear: Further Information

PEDIATRICS ◽  
1972 ◽  
Vol 49 (5) ◽  
pp. 784-785
Author(s):  
James W. Bass
Keyword(s):  
Middle Ear ◽  
The Body ◽  
Opportunity To Respond ◽  
Inactive Form ◽  
Erythromycin Base ◽  
Hydrolysis Of ◽  
Total Concentrations ◽  
Active Base

Thank you for the opportunity to respond to Dr. Meland's comments regarding our article "Erythromycin Concentrations in Middle Ear Exudates," which was published recently in the Journal. We are aware that the various esters of erythromycin are absorbed in their bacteriologically inactive form and must be hydrolyzed to active erythromycin base in the body, a process which may take considerable periods of time with certain esters of the drug. This delay in hydrolysis of erythromycin esters to the active base observed in vivo may explain why viable Hemophilus influenzae organisms were isolated from exudates with relatively high total concentrations of erythromycin as determined by the in vitro method of bioassy utilized.

scholarly journals Role for Gcs1p in Regulation of Arl1p atTrans-Golgi Compartments

2005 ◽  
Vol 16 (9) ◽  
pp. 4024-4033 ◽  
Author(s):  
Ya-Wen Liu ◽  
Chun-Fang Huang ◽  
Kai-Bin Huang ◽  
Fang-Jen S. Lee
Keyword(s):  
Dynamic Equilibrium ◽  
Vesicular Trafficking ◽  
Dependent Manner ◽  
Wild Type ◽  
Gtpase Activating Protein ◽  
Critical Components ◽  
Mutant Cells ◽  
Hydrolysis Of ◽  
Adp Ribosylation Factor

ADP-ribosylation factor (ARF) and ARF-like (ARL) proteins are members of the ARF family, which are critical components of several different vesicular trafficking pathways. ARFs have little or no detectable GTPase activity without the assistance of a GTPase-activating protein (GAP). Here, we demonstrate that yeast Gcs1p exhibits GAP activity toward Arl1p and Arf1p in vitro, and Arl1p can interact with Gcs1p in a GTP-dependent manner. Arl1p was observed both on trans-Golgi and in cytosol and was recruited from cytosol to membranes in a GTP-dependent manner. In gcs1 mutant cells, the fraction of Arl1p in cytosol relative to trans-Golgi was less than it was in wild-type cells. Increasing Gcs1p levels returned the distribution toward that of wild-type cells. Both Arl1p and Gcs1p influenced the distribution of Imh1p, an Arl1p effector. Our data are consistent with the conclusion that Arl1p moves in a dynamic equilibrium between trans-Golgi and cytosol, and the release of Arl1p from membranes in cells requires the hydrolysis of bound GTP, which is accelerated by Gcs1p.

Simultaneous Targeting of Lyn and Bcr-Abl Kinases by NS-187 Cures Mice Bearing Imatinib-Resistant Leukemic Cells.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 1518-1518
Author(s):  
Haruna Naito ◽  
Shinya Kimura ◽  
Yohei Nakaya ◽  
Haruna Naruoka ◽  
Tatsushi Wakayama ◽  
...  
Keyword(s):  
Tumor Growth ◽  
Leukemic Cell ◽  
The Body ◽  
Leukemic Cells ◽  
Pharmacokinetic Parameters ◽  
Dependent Manner ◽  
Wild Type ◽  
Imatinib Resistance

Abstract We have identified a specific dual Bcr-Abl/Lyn inhibitor, NS-187 (elsewhere described as CNS-9), which is 25–55 times more potent than imatinib against wild type Bcr-Abl in vitro. To evaluate the potential of NS-187 as a therapeutic agent, we assessed its in vivo activity. When Balb/c mice were given NS-187 orally at a dose of 30 mg/kg, the pharmacokinetic parameters were as follows: Tmax, 2 h; Cmax, 586 ng/ml; AUC0-∝, 2999 ng•h/ml; T1/2, 1.0 h; and bioavailability value (BA), 33%. The maximal tolerated dose (MTD) of NS-187 in Balb/c or Balb/c-nu/nu mice was 200 mg/kg/day (100 mg/kg, twice daily). To test the effect of NS-187 on in vivo tumor growth, Balb/c-nu/nu mice were injected subcutaneously with Bcr-Abl-positive KU812 cells on Day 0 and given NS-187 or imatinib orally twice a day from Day 7 to Day 17. At 20 mg/kg/day, imatinib inhibited tumor growth slightly, while at 200 mg/kg/day, it inhibited tumor growth almost completely. In contrast, at only 0.2 mg/kg/day NS-187 significantly inhibited tumor growth, while at 20 mg/kg/day it completely inhibited tumor growth without any adverse effects. The body weights of the treated tumor-bearing mice were not significantly different from those of untreated mice, even at a dosage of 200 mg/kg/day NS-187. Thus, NS-187 was at least 10-fold more potent than imatinib in vivo with complete inhibition of tumor growth as the end-point. We also tested the ability of NS-187 to suppress tumor growth in another murine tumor model, namely, Balb/c-nu/nu mice intravenously transplanted with BaF3 cells harboring wild type Bcr-Abl. The mice were treated orally with NS-187 or imatinib for 11 days starting on Day 1. All eight untreated mice and all eight mice treated with 400 mg/kg/day imatinib had died by Day 25 due to leukemic cell expansion, and NS-187 significantly prolonged the survival of the mice in a dose-dependent manner. We next examined the ability of NS-187 to block the in vivo growth of BaF3 cells harboring one of the Abl point-mutants M244V, G250E, Q252H, Y253F, T315I, M351T and H396P in Balb/c-nu/nu mice. These mice were treated with NS-187 or imatinib for 11 days starting on Day 1. NS-187 at 200 mg/kg/day significantly prolonged the survival of mice inoculated with BaF3 cells harboring any of these mutants except T315I compared with untreated or imatinib-treated mice (see Figure for an example). Thus, NS-187 was more potent than imatinib and could override the point-mutation-based imatinib-resistance mechanism in vivo. The efficacy and safety of NS-187 for Ph+ leukemias is expected to be verified by early-phase clinical trials. Figure Figure

scholarly journals PO 8492 REPEATED ARTEMISININ-BASED TREATMENT ON MALARIA SEXUAL PARASITE DISTRIBUTION IN POPULATION LIVING IN A MALARIA-ENDEMIC AREA OF BURKINA FASO

2019 ◽  
Vol 4 (Suppl 3) ◽  
pp. A45.2-A45
Author(s):  
Amidou Diarra ◽  
Issiaka Soulama ◽  
Issa Nebie ◽  
Maurice Ouattara ◽  
Moise Kabore ◽  
...  
Keyword(s):  
Parasite Density ◽  
Early Stage ◽  
Clinical Signs ◽  
Signs And Symptoms ◽  
Repeated Administration ◽  
Field Studies ◽  
The Body ◽  
Open Label ◽  
Feeding Experiments

BackgroundMalaria elimination and its ultimate eradication will require drugs targeting all stages of the parasite’s life cycle. Yet, very few drugs are known to be effective on the sexual stages (gametocytes) of Plasmodium falciparum. Artemisinin-based combination therapy (ACT) has been shown to have some early-stage gametocytocidal effects on in vitro and in feeding experiments. However, field studies showed that artesunate reduces but does not prevent post-treatment transmission of P. falciparum to mosquitos.Methods763 children and adult patients with acute uncomplicated Plasmodium sp. malaria were included in a phase IIIb/IV comparative, randomised, multi-centre, open label, parallel 3-arm clinical trial to assess safety and efficacy of repeated administration of pyronaridine-artesunate, dihydroartemisinin-piperaquine or artemether-lumefantrine or artesunate-amodiaquine over a two-year period. Drugs were given based on the body weight and volunteers were followed up for 42 days. Clinical signs and symptoms were recorded and filter paper and blood smears collected during each visit. Malaria parasites were assessed and parasite density development stages determined by light microscopy.ResultsP. falciparum gametocyte was 1.9%, during the two years of follow-up. From the three treatment arms, artesunate-amodiaquine was the arm bearing more P. falciparum gametocyte with 68.7%, dihydroartemisinin-piperaquine accounted for 6.3% and pyronaridine-artesunate for 25%. P. falciparum gametocyte was more pronounced in populations having parasite density ≤1 00 000 parasites/µl compared to above parasitaemia.ConclusionRepeated ACTs treatment didn’t clear P. falciparum gametocyte in a population infected with uncomplicated malaria.

scholarly journals Probing the active site of YjeE: a vital Escherichia coli protein of unknown function

2004 ◽  
Vol 384 (3) ◽  
pp. 577-584 ◽  
Author(s):  
Abdellah ALLALI-HASSANI ◽  
Tracey L. CAMPBELL ◽  
Andy HO ◽  
Jeffrey W. SCHERTZER ◽  
Eric D. BROWN
Keyword(s):  
Escherichia Coli ◽  
Unknown Function ◽  
Equilibrium Dialysis ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Wild Type ◽  
E Coli ◽  
High Affinity ◽  
Hydrolysis Of

In the study described here, we have taken steps to characterize the YjeE protein, an Escherichia coli protein of unknown function that is essential for bacterial viability. YjeE represents a protein family whose members are broadly conserved in bacteria, absent from eukaryotes and contain both Walker A and B motifs, characteristic of P-loop ATPases. We have revisited the dispensability of the yjeE gene in E. coli and describe efforts to probe the function of the YjeE protein with in vitro biochemistry. We have looked critically for ATPase activity in the recombinant E. coli protein and have made vigilant use of site-directed variants in the Walker A [K41A (Lys41→Ala) and T42A] and putative Walker B (D80Q) motifs. We noted that any hydrolysis of ATP by the wild-type E. coli protein might be attributed to background ATPase, since it was not appreciably different from that of the variants. To overcome potential contaminants, we turned to crystalline pure YjeE protein from Haemophilus influenzae that was found to hydrolyse ATP at a slow rate (kcat=1 h−1). We have also shown high-affinity binding to YjeE by ADP using equilibrium dialysis (Kd=32 μM) and by fluorescence resonance energy transfer from a conserved tryptophan in YjeE to a fluorescent derivative of ADP, 2′-/3′-O-(N-methylanthraniloyl)adenosine 5′-O-diphosphate (Kd=8 μM). Walker motif variants were notably impaired for ADP binding and T42A and D80Q mutations in yjeE were incapable of complementing the yjeE deletion strain.

Probiotic properties of a Spaceflight-induced mutant Lactobacillus plantarum SS18-50 in mice

2021 ◽  
Vol 21 ◽  
Author(s):  
Dan Wang ◽  
Tiehua Zhang ◽  
Hongwei Hao ◽  
Hongxing Zhang ◽  
Haiqing Ye ◽  
...  
Keyword(s):  
Lactobacillus Plantarum ◽  
Critical Role ◽  
The Body ◽  
Adjunctive Treatment ◽  
Probiotic Properties ◽  
Wild Type ◽  
In Vivo Experiments ◽  
Commercial Kits

Background: Probiotics are a group of bacteria that play a critical role in intestinal microbiota homeostasis and may help adjunctively treat certain diseases like metabolic and immune disorders. Objective: We recently generated a space-flight mutated Lactobacillus plantarum SS18-50 with good in vitro probiotic characteristics. In the current research, we designed two in vivo experiments to evaluate whether L. plantarum SS18-50 had the ability to increase beneficial gut bacteria, regulate oxidative status and ameliorate inflammation in mice. Methods: Experiments I: the ICR mice were gavaged with L. plantarum SS18-50 or its wild type L. plantarum GS18 at 107 or 109 CFU/kg BW daily for one month, during which the body weight was recorded weekly. The feces were collected to determine the abundance of two main beneficial bacterial groups including Lactobacillus and Bifidobacterium by selective culturing, while the total triglycerides and cholesterols in sera were determined using commercial kits. Experiment II: the mice were gavaged with loperamide hydrochloride to develop oxidative stress and inflammation phenotypes. At the same time, the experimental mice were gavaged with L. plantarum SS18-50 or wild type L. plantarum GS18 at 107 or 109 CFU/kg BW daily for one month. At the end of experiment, oxidative indicators (SOD and MDA) and inflammatory cytokines (IL-17A and IL-10) were measured by commercial kits. Results: Results showed that L. plantarum SS18-50 increased the abundance of Lactobacillus and Bifidobacterium in mice after one month’s administration. L. plantarum SS18-50 also showed the anti-oxidant activity by increasing SOD and decreasing MDA, and exerted the anti-inflammatory effect by increasing IL-10 and decreasing IL-17A in Lop treated mice. Both the wild type stain and the space mutant had such biomedical effects, but L. plantarum SS18-50 was better in increasing gut beneficial bacteria and oxidative regulation than the wild type (P<0.05). Conclusion: we conclude that L. plantarum SS18-50 has a great potential to serve as a dietary functional probiotic supplement and/or adjunctive treatment strategy.

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