scholarly journals Formimidoyltransferase cyclodeaminase prevents the starvation-induced liver hepatomegaly and dysfunction through downregulating mTORC1

PLoS Genetics ◽  
2021 ◽  
Vol 17 (12) ◽  
pp. e1009980
Author(s):  
Wenfeng Zhang ◽  
Chaoying Wu ◽  
Rui Ni ◽  
Qifen Yang ◽  
Lingfei Luo ◽  
...  
Keyword(s):  
Liver Dysfunction ◽  
Positional Cloning ◽  
Energy Homeostasis ◽  
Mammalian Target Of Rapamycin ◽  
Normal Liver ◽  
Wild Type ◽  
Starvation Response ◽  
Downstream Effector ◽  
In The Wild ◽  
High Level

The liver is a crucial center in the regulation of energy homeostasis under starvation. Although downregulation of mammalian target of rapamycin complex 1 (mTORC1) has been reported to play pivotal roles in the starvation responses, the underpinning mechanisms in particular upstream factors that downregulate mTORC1 remain largely unknown. To identify genetic variants that cause liver energy disorders during starvation, we conduct a zebrafish forward genetic screen. We identify a liver hulk (lvh) mutant with normal liver under feeding, but exhibiting liver hypertrophy under fasting. The hepatomegaly in lvh is caused by enlarged hepatocyte size and leads to liver dysfunction as well as limited tolerance to starvation. Positional cloning reveals that lvh phenotypes are caused by mutation in the ftcd gene, which encodes the formimidoyltransferase cyclodeaminase (FTCD). Further studies show that in response to starvation, the phosphorylated ribosomal S6 protein (p-RS6), a downstream effector of mTORC1, becomes downregulated in the wild-type liver, but remains at high level in lvh. Inhibition of mTORC1 by rapamycin rescues the hepatomegaly and liver dysfunction of lvh. Thus, we characterize the roles of FTCD in starvation response, which acts as an important upstream factor to downregulate mTORC1, thus preventing liver hypertrophy and dysfunction.

scholarly journals Transcriptome Analysis Provides Insights into the Mechanism of Astaxanthin Enrichment in a Mutant of the Ridgetail White Prawn Exopalaemon carinicauda

Genes ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 618
Author(s):  
Yue Jin ◽  
Shihao Li ◽  
Yang Yu ◽  
Chengsong Zhang ◽  
Xiaojun Zhang ◽  
...  
Keyword(s):  
Transcriptome Analysis ◽  
Underlying Mechanism ◽  
Biological Processes ◽  
Wild Type ◽  
Expression Levels ◽  
In The Wild ◽  
Cuticle Proteins ◽  
Apolipoprotein D ◽  
High Level ◽  
Lower Expression

A mutant of the ridgetail white prawn, which exhibited rare orange-red body color with a higher level of free astaxanthin (ASTX) concentration than that in the wild-type prawn, was obtained in our lab. In order to understand the underlying mechanism for the existence of a high level of free astaxanthin, transcriptome analysis was performed to identify the differentially expressed genes (DEGs) between the mutant and wild-type prawns. A total of 78,224 unigenes were obtained, and 1863 were identified as DEGs, in which 902 unigenes showed higher expression levels, while 961 unigenes presented lower expression levels in the mutant in comparison with the wild-type prawns. Based on Gene Ontology analysis and Kyoto Encyclopedia of Genes and Genomes analysis, as well as further investigation of annotated DEGs, we found that the biological processes related to astaxanthin binding, transport, and metabolism presented significant differences between the mutant and the wild-type prawns. Some genes related to these processes, including crustacyanin, apolipoprotein D (ApoD), cathepsin, and cuticle proteins, were identified as DEGs between the two types of prawns. These data may provide important information for us to understand the molecular mechanism of the existence of a high level of free astaxanthin in the prawn.

scholarly journals The PKS4 Gene of Fusarium graminearum Is Essential for Zearalenone Production

2006 ◽  
Vol 72 (6) ◽  
pp. 3924-3932 ◽  
Author(s):  
Erik Lys�e ◽  
Sonja S. Klemsdal ◽  
Karen R. Bone ◽  
Rasmus J. N. Frandsen ◽  
Thomas Johansen ◽  
...  
Keyword(s):  
Fusarium Graminearum ◽  
High Performance ◽  
Polyketide Synthase ◽  
Wild Type ◽  
Root Infection ◽  
Enoyl Reductase ◽  
Transformation Protocol ◽  
Chromatography Analysis ◽  
In The Wild ◽  
High Level

ABSTRACT Zearalenones are produced by several Fusarium species and can cause reproductive problems in animals. Some aurofusarin mutants of Fusarium pseudograminearum produce elevated levels of zearalenone (ZON), one of the estrogenic mycotoxins comprising the zearalenones. An analysis of transcripts from polyketide synthase genes identified in the Fusarium graminearum database was carried out for these mutants. PKS4 was the only gene with an enoyl reductase domain that had a higher level of transcription in the aurofusarin mutants than in the wild type. An Agrobacterium tumefaciens-mediated transformation protocol was used to replace the central part of the PKS4 gene with a hygB resistance gene through double homologous recombination in an F. graminearum strain producing a high level of ZON. PCR and Southern analysis of transformants were used to identify isolates with single insertional replacements of PKS4. High-performance liquid chromatography analysis showed that the PKS4 replacement mutant did not produce ZON. Thus, PKS4 encodes an enzyme required for the production of ZON in F. graminearum. Barley root infection studies revealed no alteration in the pathogenicity of the PKS4 mutant compared to the pathogenicity of the wild type. The expression of PKS13, which is located in the same cluster as PKS4, decreased dramatically in the mutant, while transcription of PKS4 was unchanged. This differential expression may indicate that ZON or its derivatives do not regulate expression of PKS4 and that the PKS4-encoded protein or its product stimulates expression of PKS13. Furthermore, both the lack of aurofusarin and ZON influenced the expression of other polyketide synthases, demonstrating that one polyketide can influence the expression of others.

scholarly journals Alterations of Metabolic and Lipid Profiles in Polymyxin-ResistantPseudomonas aeruginosa

2018 ◽  
Vol 62 (6) ◽  
Author(s):  
Mei-Ling Han ◽  
Yan Zhu ◽  
Darren J. Creek ◽  
Yu-Wei Lin ◽  
Dovile Anderson ◽  
...  
Keyword(s):  
Lipid A ◽  
Therapeutic Option ◽  
Polymyxin B ◽  
Multidrug Resistant ◽  
Wild Type ◽  
Metabolomics Data ◽  
Content Type ◽  
In The Wild ◽  
High Level ◽  
Acyl Coenzyme A

ABSTRACTMultidrug-resistantPseudomonas aeruginosapresents a global medical challenge, and polymyxins are a key last-resort therapeutic option. Unfortunately, polymyxin resistance inP. aeruginosahas been increasingly reported. The present study was designed to define metabolic differences between paired polymyxin-susceptible and -resistantP. aeruginosastrains using untargeted metabolomics and lipidomics analyses. The metabolomes of wild-typeP. aeruginosastrain K ([PAK] polymyxin B MIC, 1 mg/liter) and its pairedpmrBmutant strains, PAKpmrB6and PAKpmrB12(polymyxin B MICs of 16 mg/liter and 64 mg/liter, respectively) were characterized using liquid chromatography-mass spectrometry, and metabolic differences were identified through multivariate and univariate statistics. PAKpmrB6and PAKpmrB12, which displayed lipid A modifications with 4-amino-4-deoxy-l-arabinose, showed significant perturbations in amino acid and carbohydrate metabolism, particularly the intermediate metabolites from 4-amino-4-deoxy-l-arabinose synthesis and the methionine salvage cycle pathways. The genomics result showed a premature termination (Y275stop) inspeE(encoding spermidine synthase) in PAKpmrB6, and metabolomics data revealed a decreased intracellular level of spermidine in PAKpmrB6compared to that in PAKpmrB12. Our results indicate that spermidine may play an important role in high-level polymyxin resistance inP. aeruginosa. Interestingly, bothpmrBmutants had decreased levels of phospholipids, fatty acids, and acyl-coenzyme A compared to those in the wild-type PAK. Moreover, the more resistant PAKpmrB12mutant exhibited much lower levels of phospholipids than the PAKpmrB6mutant, suggesting that the decreased phospholipid level was associated with polymyxin resistance. In summary, this study provides novel mechanistic information on polymyxin resistance inP. aeruginosaand highlights its impacts on bacterial metabolism.

scholarly journals Mutation of a palmitoyltransferase ZDHHC18-like gene is responsible for the minute wing mutation in the silkworm (Bombyx mori)

2017 ◽  
Author(s):  
Ye Yu ◽  
Xiaojing Liu ◽  
Xiao Ma ◽  
Zhongjie Zhang ◽  
Na Liu ◽  
...  
Keyword(s):  
Bombyx Mori ◽  
Positional Cloning ◽  
Molecular Mechanisms ◽  
Adult Stage ◽  
Significant Proportion ◽  
Gene Promoter ◽  
Wild Type ◽  
Evolutionarily Conserved ◽  
In The Wild ◽  
Hippo Signalling

AbstractPulpal- and adult-stage minute wing (mw) mutants of the silkworm Bombyx mori have much smaller wings than those of the wild type. Herein, we report the genetic and molecular mechanisms underling the formation of the minute wing. Fine mapping and positional cloning revealed that a palmitoyltransferase ZDHHC18-like gene (BmAPP）was responsible for the mw mutation. CRISPR/Cas9 screening of the BmAPP gene in wild-type embryos revealed that a significant proportion of adults had the mw mutation. In an mw mutant strain, u11, a 10-bp insertion in the promoter of a novel gene resulted in low-level translation of a protein belonging to the DHHC family. A PiggyBac-based transgenic analysis showed that the promoter induced the expression of aBmAPP gene promoter in the wild type but not the mw mutant. These findings indicate that functional deletion of this gene promoter accounts for the mw mutation in silkworm. The possibility that BmAPP gene is involved in Hippo signalling pathway, an evolutionarily conserved signaling pathway that controls organ size, is discussed.

Functional overlap of the dictyostelium RasG, RasD and RasB proteins

2000 ◽  
Vol 113 (8) ◽  
pp. 1427-1434 ◽  
Author(s):  
M. Khosla ◽  
G.B. Spiegelman ◽  
R. Insall ◽  
G. Weeks
Keyword(s):  
Western Blot ◽  
Blot Analysis ◽  
Western Blot Analysis ◽  
Ras Proteins ◽  
Wild Type ◽  
Vegetative Cells ◽  
Protein Levels ◽  
Ras Genes ◽  
Downstream Effector ◽  
In The Wild

Disruption of the rasG gene in Dictyostelium discoideum results in several distinct phenotypes: a defect in cytokinesis, reduced motility and reduced growth. Reintroduction of the rasG gene restores all of the properties of the rasG(-) cells to those of the wild type. To determine whether the defects are due to impaired interactions with a single or multiple downstream effectors, we tested the ability of the highly related but non identical Dictyostelium ras genes, rasD and rasB, to rescue the defects. Introduction of the rasD gene under the control of the rasG promoter into rasG null (rasG(-)) cells corrected all phenotypes except the motility defect, suggesting that motility is regulated by a RasG mediated pathway that is different to those regulating growth or cytokinesis. Western blot analysis of RasD protein levels revealed that vegetative rasG(-)cells contained considerably more protein than the parental AX-3 cells, suggesting that RasD protein levels are negatively regulated in vegetative cells by RasG. The level of RasD was enhanced when the rasD gene was introduced under the control of the rasG promoter, and this increase in protein is presumably responsible for the reversal of the growth and cytokinesis defects of the rasG(-)cells. Thus, RasD protein levels are controlled by the level of RasG, but not by the level of RasD. Introduction of the rasB gene under the control of the rasG promoter into rasG(-) cells produced a complex phenotype. The transformants were extremely small and mononucleate and exhibited enhanced motility. However, the growth of these cells was considerably slower than the growth of the rasG(-) cells, suggesting the possibility that high levels of RasB inhibit an essential process. This was confirmed by expressing rasB in wild-type cells; the resulting transformants exhibited severely impaired growth. When RasB protein levels were determined by western blot analysis, it was found that levels were higher in the rasG(-)cells than they were in the wild-type parental, suggesting that RasG also negatively regulates rasB expression in vegetative cells. Overexpression of rasB in the rasG(-)cells also reduced the level of RasD protein. In view of the fact that alternate Ras proteins correct some, but not all, of the defects exhibited by the rasG(-) cells, we propose that RasG interacts with more than one downstream effector. In addition, it is clear that the levels of the various Ras proteins are tightly regulated in vegetative cells and that overexpression can be deleterious.

scholarly journals Sensitivity of Populations of Botrytis cinerea from Pear-Related Sources to Benzimidazole and Dicarboximide Fungicides

Plant Disease ◽  
2003 ◽  
Vol 87 (6) ◽  
pp. 645-649 ◽  
Author(s):  
Cheryl L. Lennox ◽  
Robert A. Spotts
Keyword(s):  
Botrytis Cinerea ◽  
Pacific Northwest ◽  
Wild Type ◽  
Baseline Sensitivity ◽  
Benzimidazole Fungicides ◽  
Postharvest Application ◽  
The Pacific ◽  
In The Wild ◽  
Type Population ◽  
High Level

Botrytis cinerea is responsible for a major portion of postharvest decay in winter pears in the Pacific Northwest. The baseline sensitivity levels (mean EC50 values) of a wild-type B. cinerea population to thiabendazole and iprodione were 6.66 and 0.56 mg/liter, respectively. B. cinerea from commercial orchards not treated with a benzimidazole had significantly lower incidence of resistance (0.59%) to a discriminatory concentration of thiabendazole at 10 mg/liter than did isolates from orchards in which benomyl had been applied for experimental purposes (16.0%), unsprayed control trees in benomyl-sprayed orchards (5.34%), and isolates from packinghouses where thiabendazole was applied as a prestorage drench or packingline spray (3.23%). The mean EC50 value of isolates in the wild-type population was lower than those of resistant isolates from all other sources. High-level thiabendazole resistance (EC50 > 100 mg/liter) was found in 0.20% of isolates from unsprayed commercial orchards, 9.33% of isolates from benomyl-sprayed orchards, and 2.67% of isolates from unsprayed control trees in these benomyl-sprayed orchards. In isolates from packinghouses where a thiabendazole line spray was applied, 1.52% had high-level thiabendazole resistance. All isolates from all pear-related sources tested were sensitive to iprodione at 10 mg/liter. This study provides evidence supporting current recommendations of a single postharvest application of a benzimidazole to control decay caused by B. cinerea, and no application of benzimidazole fungicides in the orchard.

scholarly journals Role of Maltogenic Amylase and Pullulanase in Maltodextrin and Glycogen Metabolism of Bacillus subtilis 168

2009 ◽  
Vol 191 (15) ◽  
pp. 4835-4844 ◽  
Author(s):  
Jae-Hoon Shim ◽  
Jong-Tae Park ◽  
Jung-Sun Hong ◽  
Ki Woo Kim ◽  
Myo-Jeong Kim ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Glycogen Metabolism ◽  
Outer Side ◽  
Wild Type ◽  
Amylolytic Enzymes ◽  
In The Wild ◽  
Maltogenic Amylase ◽  
Molecular Masses ◽  
Average Molecular Masses ◽  
High Level

ABSTRACT The physiological functions of two amylolytic enzymes, a maltogenic amylase (MAase) encoded by yvdF and a debranching enzyme (pullulanase) encoded by amyX, in the carbohydrate metabolism of Bacillus subtilis 168 were investigated using yvdF, amyX, and yvdF amyX mutant strains. An immunolocalization study revealed that YvdF was distributed on both sides of the cytoplasmic membrane and in the periplasm during vegetative growth but in the cytoplasm of prespores. Small carbohydrates such as maltoheptaose and β-cyclodextrin (β-CD) taken up by wild-type B. subtilis cells via two distinct transporters, the Mdx and Cyc ABC transporters, respectively, were hydrolyzed immediately to form smaller or linear maltodextrins. On the other hand, the yvdF mutant exhibited limited degradation of the substrates, indicating that, in the wild type, maltodextrins and β-CD were hydrolyzed by MAase while being taken up by the bacterium. With glycogen and branched β-CDs as substrates, pullulanase showed high-level specificity for the hydrolysis of the outer side chains of glycogen with three to five glucosyl residues. To investigate the roles of MAase and pullulanase in glycogen utilization, the following glycogen-overproducing strains were constructed: a glg mutant with a wild-type background, yvdF glg and amyX glg mutants, and a glg mutant with a double mutant (DM) background. The amyX glg and glg DM strains accumulated significantly larger amounts of glycogen than the glg mutant, while the yvdF glg strain accumulated an intermediate amount. Glycogen samples from the amyX glg and glg DM strains exhibited average molecular masses two and three times larger, respectively, than that of glycogen from the glg mutant. The results suggested that glycogen breakdown may be a sequential process that involves pullulanase and MAase, whereby pullulanase hydrolyzes the α-1,6-glycosidic linkage at the branch point to release a linear maltooligosaccharide that is then hydrolyzed into maltose and maltotriose by MAase.

Freeze-substituted fungal cells of Nectria haematococca: A comparison of the macroconidial walls of the adhesion-competent wild type with an adhesion-reduced mutant

1990 ◽  
Vol 48 (3) ◽  
pp. 688-689
Author(s):  
Thecan Caesar-Ton That ◽  
Lynn Epstein
Keyword(s):  
Freeze Substitution ◽  
Uranyl Acetate ◽  
Wild Type ◽  
Nectria Haematococca ◽  
Fruit Extract ◽  
Dialysis Tubing ◽  
Tube Emergence ◽  
Contrast Microscopy ◽  
In The Wild ◽  
Freeze Damage

Nectria haematococca mating population I (anamorph, Fusarium solani) macroconidia attach to its host (squash) and non-host surfaces prior to germ tube emergence. The macroconidia become adhesive after a brief period of protein synthesis. Recently, Hickman et al. (1989) isolated N. haematococca adhesion-reduced mutants. Using freeze substitution, we compared the development of the macroconidial wall in the wild type in comparison to one of the mutants, LEI.Macroconidia were harvested at 1C, washed by centrifugation, resuspended in a dilute zucchini fruit extract and incubated from 0 - 5 h. During the incubation period, wild type macroconidia attached to uncoated dialysis tubing. Mutant macroconidia did not attach and were collected on poly-L-lysine coated dialysis tubing just prior to freezing. Conidia on the tubing were frozen in liquid propane at 191 - 193C, substituted in acetone with 2% OsO4 and 0.05% uranyl acetate, washed with acetone, and flat-embedded in Epon-Araldite. Using phase contrast microscopy at 1000X, cells without freeze damage were selected, remounted, sectioned and post-stained sequentially with 1% Ba(MnO4)2 2% uranyl acetate and Reynold’s lead citrate. At least 30 cells/treatment were examined.

scholarly journals Mutations in fbiD (Rv2983) as a Novel Determinant of Resistance to Pretomanid and Delamanid in Mycobacterium tuberculosis

2020 ◽  
Vol 65 (1) ◽  
pp. e01948-20
Author(s):  
Dalin Rifat ◽  
Si-Yang Li ◽  
Thomas Ioerger ◽  
Keshav Shah ◽  
Jean-Philippe Lanoix ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Clinical Evidence ◽  
Clinical Samples ◽  
Loss Of Function ◽  
Wild Type ◽  
Content Type ◽  
Solid Media ◽  
High Level ◽  
Level Resistance

ABSTRACTThe nitroimidazole prodrugs delamanid and pretomanid comprise one of only two new antimicrobial classes approved to treat tuberculosis (TB) in 50 years. Prior in vitro studies suggest a relatively low barrier to nitroimidazole resistance in Mycobacterium tuberculosis, but clinical evidence is limited to date. We selected pretomanid-resistant M. tuberculosis mutants in two mouse models of TB using a range of pretomanid doses. The frequency of spontaneous resistance was approximately 10−5 CFU. Whole-genome sequencing of 161 resistant isolates from 47 mice revealed 99 unique mutations, of which 91% occurred in 1 of 5 genes previously associated with nitroimidazole activation and resistance, namely, fbiC (56%), fbiA (15%), ddn (12%), fgd (4%), and fbiB (4%). Nearly all mutations were unique to a single mouse and not previously identified. The remaining 9% of resistant mutants harbored mutations in Rv2983 (fbiD), a gene not previously associated with nitroimidazole resistance but recently shown to be a guanylyltransferase necessary for cofactor F420 synthesis. Most mutants exhibited high-level resistance to pretomanid and delamanid, although Rv2983 and fbiB mutants exhibited high-level pretomanid resistance but relatively small changes in delamanid susceptibility. Complementing an Rv2983 mutant with wild-type Rv2983 restored susceptibility to pretomanid and delamanid. By quantifying intracellular F420 and its precursor Fo in overexpressing and loss-of-function mutants, we provide further evidence that Rv2983 is necessary for F420 biosynthesis. Finally, Rv2983 mutants and other F420H2-deficient mutants displayed hypersusceptibility to some antibiotics and to concentrations of malachite green found in solid media used to isolate and propagate mycobacteria from clinical samples.

scholarly journals Allelic Exchange and Mutant Selection Demonstrate that Common Clinical embCAB Gene Mutations Only Modestly Increase Resistance to Ethambutol in Mycobacterium tuberculosis

2009 ◽  
Vol 54 (1) ◽  
pp. 103-108 ◽  
Author(s):  
Hassan Safi ◽  
Robert D. Fleischmann ◽  
Scott N. Peterson ◽  
Marcus B. Jones ◽  
Behnam Jarrahi ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
In Vitro Selection ◽  
Gene Mutations ◽  
Wild Type ◽  
Mutant Selection ◽  
Preferential Growth ◽  
Allelic Exchange ◽  
High Level ◽  
Isogenic Mutants

ABSTRACT Mutations within codon 306 of the Mycobacterium tuberculosis embB gene modestly increase ethambutol (EMB) MICs. To identify other causes of EMB resistance and to identify causes of high-level resistance, we generated EMB-resistant M. tuberculosis isolates in vitro and performed allelic exchange studies of embB codon 406 (embB406) and embB497 mutations. In vitro selection produced mutations already identified clinically in embB306, embB397, embB497, embB1024, and embC13, which result in EMB MICs of 8 or 14 μg/ml, 5 μg/ml, 12 μg/ml, 3 μg/ml, and 4 μg/ml, respectively, and mutations at embB320, embB324, and embB445, which have not been identified in clinical M. tuberculosis isolates and which result in EMB MICs of 8 μg/ml, 8 μg/ml, and 2 to 8 μg/ml, respectively. To definitively identify the effect of the common clinical embB497 and embB406 mutations on EMB susceptibility, we created a series of isogenic mutants, exchanging the wild-type embB497 CAG codon in EMB-susceptible M. tuberculosis strain 210 for the embB497 CGG codon and the wild-type embB406 GGC codon for either the embB406 GCC, embB406 TGC, embB406 TCC, or embB406 GAC codon. These new mutants showed 6-fold and 3- to 3.5-fold increases in the EMB MICs, respectively. In contrast to the embB306 mutants, the isogenic embB497 and embB406 mutants did not have preferential growth in the presence of isoniazid or rifampin (rifampicin) at their MICs. These results demonstrate that individual embCAB mutations confer low to moderate increases in EMB MICs. Discrepancies between the EMB MICs of laboratory mutants and clinical M. tuberculosis strains with identical mutations suggest that clinical EMB resistance is multigenic and that high-level EMB resistance requires mutations in currently unknown loci.

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