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1.
Ren Fail ; 45(2): 2254569, 2023.
Article in English | MEDLINE | ID: mdl-37755153

ABSTRACT

Coronary artery calcification (CAC) is common in dialysis patients and is associated with a higher risk of future cardiovascular events. Sodium thiosulfate (STS) is effective for calciphylaxis in dialysis patients; however, the influence of STS on CAC in dialysis patients remains unclear. This systematic review and meta-analysis were conducted to evaluate the effects of STS on CAC in patients undergoing dialysis. PubMed, Embase, Cochrane Library, CNKI, and Wanfang databases were searched from inception to 22 March 2023 for controlled studies comparing the influence of STS versus usual care without STS on CAC scores in dialysis patients. A random effects model incorporating the potential influence of heterogeneity was used to pool the results. Nine studies, including two non-randomized studies and seven randomized controlled trials, were included in the meta-analysis. Among these, 365 patients on dialysis were included in the study. Compared with usual care without STS, intravenous STS for 3-6 months was associated with significantly reduced CAC scores (mean difference [MD] = -180.17, 95% confidence interval [CI]: -276.64 to -83.70, p < 0.001, I2 = 0%). Sensitivity analysis limited to studies of patients on hemodialysis showed similar results (MD: -167.33, 95% CI: -266.57 to -68.09, p = 0.001; I2 = 0%). Subgroup analyses according to study design, sample size, mean age, sex, dialysis vintage of the patients, and treatment duration of STS also showed consistent results (p for subgroup differences all > 0.05). In conclusion, intravenous STS may be effective in attenuating CAC in dialysis patients.


Subject(s)
Coronary Artery Disease , Thiosulfates , Vascular Calcification , Humans , Renal Dialysis , Thiosulfates/therapeutic use , Vascular Calcification/prevention & control
2.
BMC Nephrol ; 23(1): 313, 2022 09 16.
Article in English | MEDLINE | ID: mdl-36114523

ABSTRACT

BACKGROUND: The M-type phospholipase A2 receptor (PLA2R)-associated idiopathic membranous nephropathy (IMN) is a common immune-related disease in adults. Vascular endothelial growth factor A (VEGFA) is the key mediator of angiogenesis, which leads to numerous kidney diseases. However, the role of VEGFA in IMN is poorly understood. METHODS: In the present study, we downloaded the microarray data GSE115857 from Gene Expression Omnibus (GEO). The differentially expressed genes (DEGs) were identified with R software. The cytoHubba plug-in were used to identify hub genes from the protein-protein interaction network. Gene set enrichment analysis (GSEA) was used to identify signalling pathway in IMN. CCK8 was performed to assess the cell viability in human vascular endothelial cells (HVECs). Then, passive Heymann nephritis (PHN) was induced in rats by a single tail vein injection of anti-Fx1A antiserum. Animals treated with VEGFA inhibitor bevacizumab (BV), with saline as a positive control. Proteinuria was evaluated by biochemical measurements. Immunohistochemistry and immunofluorescence was used to evaluate relative proteins expression. Electron microscopy was performed to observe the thickness of the glomerular basement membrane (GBM). RESULTS: We revealed 3 hub genes, including one up-regulated gene VEGFA and two down-regulated genes JUN and FOS, which are closely related to the development of PLA2R-associated IMN. Pathway enrichment analysis found that the biological process induced by VEGFA is associated with PI3K/Akt signalling. GSEA showed that the signalling pathway of DEGs in GSE115857 was focused on angiogenesis, in which VEGFA acts as a core gene. We confirmed the high expression of VEGFA, PI3K, and AKT in IMN renal biopsy samples with immunohistochemistry. In HVECs, we found that BV suppresses cell viability in a time and dose dependent manner. In vivo, we found low dose of BV attenuates proteinuria via inhibiting VEGFA/PI3K/AKT signalling. Meanwhile, low dose of BV alleviates the thickening of the GBM. CONCLUSION: VEGFA/PI3K/AKT signalling may play significant roles in the pathogenesis of IMN, which may provide new targets for the treatment of IMN.


Subject(s)
Glomerulonephritis, Membranous , Receptors, Phospholipase A2 , Vascular Endothelial Growth Factor A/metabolism , Adult , Animals , Bevacizumab , Endothelial Cells/metabolism , Glomerulonephritis, Membranous/drug therapy , Humans , Phosphatidylinositol 3-Kinases , Proteinuria , Proto-Oncogene Proteins c-akt , Rats , Receptors, Phospholipase A2/genetics
3.
J Healthc Eng ; 2022: 1469370, 2022.
Article in English | MEDLINE | ID: mdl-35422982

ABSTRACT

In order to compare the effects of iopromide and isoxazole on postoperative contrast-induced nephropathy in patients with renal insufficiency, the paper searches for randomized controlled trials and retrospective cohort studies comparing the effects of iopromide and iodixanol on renal function in patients with renal insufficiency after surgery. The data are extracted from eligible studies. We tried to assess the incidence of contrast-agent nephropathy, preoperative and postoperative serum creatinine indicators, and mortality. This paper includes 8 studies with a total of 1243 patients. The incidence of contrast-induced nephropathy in the iopromide group is higher than that in the iodixanol group, and there is no significant difference between the two groups in postoperative mortality and preoperative serum creatinine expression. Sensitivity analysis and funnel chart show that our research is robust and has low publication bias. Our research shows that in patients with renal insufficiency, the incidence of contrast-medium nephropathy in the iopromide group is higher than that in the iodixanol group. Iodixanol is safer and has less effect on patients' serum creatinine levels.


Subject(s)
Kidney Diseases , Renal Insufficiency , Contrast Media/adverse effects , Creatinine/adverse effects , Female , Humans , Iohexol/analogs & derivatives , Kidney Diseases/chemically induced , Male , Renal Insufficiency/chemically induced , Renal Insufficiency/complications , Renal Insufficiency/epidemiology , Retrospective Studies , Triiodobenzoic Acids
4.
Int J Gen Med ; 14: 857-866, 2021.
Article in English | MEDLINE | ID: mdl-33758533

ABSTRACT

OBJECTIVE: This study aims to investigate the clinical value of serum Klotho and FGF23 in cardiac valve calcification in patients with chronic kidney disease (CKD). METHODS: In the present study, 180 patients with CKD, who were admitted to the department of nephrology of our hospital on April 1, 2016 (solstice, 2019), were selected as the main subjects. According to the CKD stage, these patients were divided into three groups: CKD2~3 group, CKD4 group, and CKD5 group. In each group, ultrasound was used to evaluate the cardiac valve calcification, and the independent risk factors for cardiac valve calcification were analyzed by Logistic regression. RESULTS: The levels of hemoglobin and blood calcium in CKD2~3 patients were higher than those in CKD4 and CKD5 patients, and the levels of hemoglobin and blood calcium in CKD5 patients were higher than those in CKD4 patients (P<0.05). Albumin was lower in CKD2~3 patients when compared to CKD5 patients while albumin was higher in CKD5 patients when compared to CKD4 patients (P<0.05). The serum levels of FGF23 was lower in CKD2~3 patients when compared to CKD4 and CKD5 patients while the serum levels of FGF23 was lower in CKD4 patients when compared to CKD5 patients (P<0.05). The serum levels of Klotho was higher in CKD2~3 patients, when compared to CKD4 and CKD5 patients, while the serum levels of Klotho was higher in CKD4 patients, when compared to CKD5 patients (P<0.05). The logistic regression analysis revealed that GFR, serum creatinine, FGF23 and Klotho were independent risk factors for cardiac valve calcification in patients with CKD. CONCLUSION: With the decrease of GFR in CKD patients, the serum levels of FGF23 increases, while the serum levels of Klotho decreases. Furthermore, the serum levels of FGF23 and Klotho are affected by various factors, and the levels of FGF23 and Klotho in CKD patients are negatively correlated. GFR, serum creatinine, FGF23 and Klotho are independent risk factors for heart valve calcification in patients with CKD.

5.
Kaohsiung J Med Sci ; 35(7): 393-400, 2019 Jul.
Article in English | MEDLINE | ID: mdl-31001900

ABSTRACT

Vascular calcification (VC) plays as a critical role on cardiovascular disease (CVD) and acts as a notable risk factor in cardiovascular system. Vascular smooth muscle cells (VSMCs) calcification can be triggered by high phosphate treatment; however, the explicit mechanism remains unclear. In the present study, we isolated VSMCs from primary rat artery, applied ß-GP (ß-glycerophosphate) for inducing VSMCs calcification in vitro to explore the mechanism of phosphate-induced calcification in VSMCs. Alizarin red staining was performed to assess the mineralization in VSMCs. Calcium deposition experiment was taken to evaluate the calcium content. ALP staining was determined to assess the ALP activity. The recombinant adenoviruses were constructed for the overexpression of Klotho and FGF23, respectively. qRT-PCR and western blot analysis were subjected to measure the expression of Klotho/FGF23 and correlated genes among Wnt7b/ß-catenin pathway. We found that the calcium content was obviously increased and Alizarin red staining was positive in calcification group exposure with high phosphate in a time-dependent manner. The expression of Klotho and FGF23 was significantly decreased in the calcification group. However, overexpression of Klotho and FGF23 markedly reversed VSMCs calcification stimulating with high phosphate treatment. Moreover, Wnt7b/ß-catenin inhibitor DKK1 could partly attenuate the effect of high phosphate on calcified VSMCs. These findings demonstrated that Klotho/FGF23 axis could modulate high phosphate-induced VSMCs calcification via Wnt7b/ß-catenin signaling pathway. Our findings unravel that Klotho/FGF23- Wnt7b/ß-catenin axis functions as a crucial role in the VSMCs calcification.


Subject(s)
Fibroblast Growth Factors/genetics , Glucuronidase/genetics , Glycerophosphates/pharmacology , Myocytes, Smooth Muscle/drug effects , Vascular Calcification/genetics , Wnt Proteins/genetics , beta Catenin/genetics , Alkaline Phosphatase/genetics , Alkaline Phosphatase/metabolism , Animals , Aorta/cytology , Aorta/metabolism , Calcium/metabolism , Fibroblast Growth Factor-23 , Fibroblast Growth Factors/metabolism , Gene Expression Regulation , Glucuronidase/metabolism , Humans , Intercellular Signaling Peptides and Proteins/biosynthesis , Intercellular Signaling Peptides and Proteins/pharmacology , Klotho Proteins , Male , Myocytes, Smooth Muscle/cytology , Myocytes, Smooth Muscle/metabolism , Primary Cell Culture , Rats , Rats, Sprague-Dawley , Recombinant Proteins/biosynthesis , Recombinant Proteins/pharmacology , Signal Transduction , Wnt Proteins/antagonists & inhibitors , Wnt Proteins/metabolism , beta Catenin/antagonists & inhibitors , beta Catenin/metabolism
6.
Nat Commun ; 9(1): 5200, 2018 12 05.
Article in English | MEDLINE | ID: mdl-30518851

ABSTRACT

BRD4 assembles transcriptional machinery at gene super-enhancer regions and governs the expression of genes that are critical for cancer progression. However, it remains unclear whether BRD4-mediated gene transcription is required for tumor cells to develop drug resistance. Our data show that prolonged treatment of luminal breast cancer cells with AKT inhibitors induces FOXO3a dephosphorylation, nuclear translocation, and disrupts its association with SirT6, eventually leading to FOXO3a acetylation as well as BRD4 recognition. Acetylated FOXO3a recognizes the BD2 domain of BRD4, recruits the BRD4/RNAPII complex to the CDK6 gene promoter, and induces its transcription. Pharmacological inhibition of either BRD4/FOXO3a association or CDK6 significantly overcomes the resistance of luminal breast cancer cells to AKT inhibitors in vitro and in vivo. Our study reports the involvement of BRD4/FOXO3a/CDK6 axis in AKTi resistance and provides potential therapeutic strategies for treating resistant breast cancer.


Subject(s)
Breast Neoplasms/metabolism , Cyclin-Dependent Kinase 6/metabolism , Forkhead Box Protein O3/metabolism , Nuclear Proteins/metabolism , Proto-Oncogene Proteins c-akt/metabolism , Transcription Factors/metabolism , Acetylation/drug effects , Animals , Breast Neoplasms/drug therapy , Breast Neoplasms/genetics , Cell Cycle Proteins , Cell Line, Tumor , Cell Nucleus/genetics , Cell Nucleus/metabolism , Cyclin-Dependent Kinase 6/genetics , Female , Forkhead Box Protein O3/genetics , Gene Expression Regulation , Heterocyclic Compounds, 3-Ring/administration & dosage , Humans , Mice , Mice, Nude , Nuclear Proteins/chemistry , Nuclear Proteins/genetics , Oxadiazoles/administration & dosage , Promoter Regions, Genetic , Protein Binding/drug effects , Protein Domains , Protein Kinase Inhibitors/administration & dosage , Protein Transport/drug effects , Proto-Oncogene Proteins c-akt/antagonists & inhibitors , Proto-Oncogene Proteins c-akt/genetics , Pyrimidines/administration & dosage , Pyrroles/administration & dosage , Sirtuins/genetics , Sirtuins/metabolism , Transcription Factors/chemistry , Transcription Factors/genetics
7.
Sci Rep ; 5: 10625, 2015 May 29.
Article in English | MEDLINE | ID: mdl-26023866

ABSTRACT

Bax inhibitor 1 (BI-1) is a highly conserved protein originally identified as a suppressor of the proapoptotic protein Bax to inhibit cell death in animals and plants. The orthologs of BI-1 are widely distributed in filamentous fungi but their functions remain largely unknown. Herein, we report the identification and characterizations of MrBI-1, an ortholog of BI-1, in the entomopathogenic fungus Metarhizium robertsii. First, we found that MrBI-1 could partially rescue mammalian Bax-induced cell death in yeast. Deletion of MrBI-1 impaired fungal development, virulence and heat tolerance in M. robertsii. We also demonstrated that inactivation of MrBI-1 reduced fungal resistance to farnesol but not to hydrogen peroxide, suggesting that MrBI-1 contributes to antiapoptotic-like cell death via the endoplasmic reticulum stress-signaling pathway rather than the classical mitochondrium-dependent pathway. In particular, we found that unlike the observations in yeasts and plants, expression of mammalian Bax did not lead to a lethal effect in M. robertsii; however, it did aggravate the fungal apoptotic effect of farnesol. The results of this study advance our understanding of BI-1-like protein functions in filamentous fungi.


Subject(s)
Adaptation, Biological , Apoptosis , Fungal Proteins/metabolism , Hot Temperature , Metarhizium/physiology , bcl-2-Associated X Protein/antagonists & inhibitors , Fungal Proteins/chemistry , Fungal Proteins/genetics , Gene Deletion , Hydrogen Peroxide/pharmacology , Metarhizium/classification , Metarhizium/drug effects , Metarhizium/pathogenicity , Microbial Viability/drug effects , Microbial Viability/genetics , Phenotype , Phylogeny , Protein Interaction Domains and Motifs , Spores, Fungal , Virulence , bcl-2-Associated X Protein/metabolism
8.
Appl Biochem Biotechnol ; 176(2): 636-44, 2015 May.
Article in English | MEDLINE | ID: mdl-25855238

ABSTRACT

A novel microbial strain JD115 capable of degrading acetochlor was isolated from the sludge of acetochlor manufacture and was identified as Pseudomonas aeruginosa species. This strain was able to grow on acetochlor as the sole source of both carbon and nitrogen. The biodegradation of acetochlor by strain JD115 could be described either by the pseudo-first-order or by the second-order kinetics models, while the latter gave a better performance. The strain optimally degraded acetochlor at a pH value of 7.0 and a temperature of 37 °C. Additional nutriments could greatly enhance the degradation rate of acetochlor up to 95.4% in the presence of 50 mg acetochlor l(-1). The metabolite analyses by GC-MS presumed that catechol was an intermediate product of acetochlor, which was finally degraded for 5 days of incubation. This study highlights the potential use of this strain for the bioremediation of an acetochlor-polluted environment.


Subject(s)
Models, Biological , Pseudomonas/metabolism , Toluidines/metabolism , Biodegradation, Environmental , Pseudomonas/isolation & purification , Sewage/microbiology
9.
Genetics ; 199(2): 487-96, 2015 Feb.
Article in English | MEDLINE | ID: mdl-25527286

ABSTRACT

Rho signaling regulates a variety of biological processes, but whether it is implicated in aging remains an open question. Here we show that a guanine nucleotide exchange factor of the Dbl family, OSG-1, confers functional aging by dysregulating Rho GTPases activities in C. elegans. Thus, gene reporter analysis revealed widespread OSG-1 expression in muscle and neurons. Loss of OSG-1 gene function was not associated with developmental defects. In contrast, suppression of OSG-1 lessened loss of function (chemotaxis) in ASE sensory neurons subjected to conditions of oxidative stress generated during natural aging, by oxidative challenges, or by genetic mutations. RNAi analysis showed that OSG-1 was specific toward activation of RHO-1 GTPase signaling. RNAi further implicated actin-binding proteins ARX-3 and ARX-5, thus the actin cytoskeleton, as one of the targets of OSG-1/RHO-1 signaling. Taken together these data suggest that OSG-1 is recruited under conditions of oxidative stress, a hallmark of aging, and contributes to promote loss of neuronal function by affecting the actin cytoskeleton via altered RHO-1 activity.


Subject(s)
Aging/genetics , Caenorhabditis elegans Proteins/genetics , Caenorhabditis elegans Proteins/metabolism , Caenorhabditis elegans/genetics , Caenorhabditis elegans/metabolism , Neurons/metabolism , Signal Transduction , rho GTP-Binding Proteins/metabolism , Amyloid beta-Peptides/genetics , Animals , Animals, Genetically Modified , Chromosome Mapping , Dendrites/metabolism , Gene Expression , Genes, Reporter , Genetic Loci , Humans , Longevity/genetics , Muscles/metabolism , Oxidative Stress , Phenotype , Protein Binding
10.
Water Sci Technol ; 69(10): 1971-83, 2014.
Article in English | MEDLINE | ID: mdl-24845311

ABSTRACT

The universal microbial cometabolism provides us with an effective approach to remove man-made xenobiotics. However, the cometabolic bioremediation of toxic organic compounds has not been widely initiated due to the obscure underlying fundamentals in the studies or applications of microbial cometabolism. This review summarizes the current research trends in mechanistic understanding of microbial cometabolism, especially with regard to its potential applications. The crucial factors including key enzyme, enzyme inhibition, toxic effects and energy regulation are discussed, which all significantly contribute to the cometabolic bioremediation of pollutants. The presented review of chlorinated ethylene cometabolism in this overview has further confirmed the fundamentals and hypotheses mentioned above, and thus cometabolism of chlorinated ethylenes has been regarded as a role model of pollution remediation technology using microbial cometabolism. The subsequent prospective research should provide insights into the ambiguous mechanism of microbial cometabolism and help us to develop more efficient bioremediation of progressive pollution.


Subject(s)
Bacteria/metabolism , Biodegradation, Environmental , Ethylenes/metabolism , Hydrocarbons, Chlorinated/metabolism , Water Pollutants, Chemical/metabolism , Bioreactors , Ethylenes/chemistry , Hydrocarbons, Chlorinated/chemistry , Water Pollutants, Chemical/chemistry
11.
PLoS One ; 8(11): e79790, 2013.
Article in English | MEDLINE | ID: mdl-24223195

ABSTRACT

BACKGROUND: Aging is a biological process strongly determined by genetics. However, only a few single nucleotide polymorphisms (SNPs) have been reported to be consistently associated with aging. While investigating whether copy number variations (CNVs) could fill this gap, we focused on CNVs that have not been studied in previous SNP-based searches via tagging SNPs. METHODS: TaqMan qPCR assays were developed to quantify 20 common CNVs in 222 senior American Caucasians in order to reveal possible association with longevity. The replication study was comprised of 1283 community-dwelling senior European Caucasians. Replicated CNVs were further investigated for association with healthy aging and aging-related diseases, while association with longevity was additionally tested in Caenorhabditis elegans. RESULTS: In the discovery study of ≥80 vs.<80 years old seniors, a homozygous intronic CNV deletion in the CNTNAP4 gene was inversely associated with survival to the age of 80 (OR=0.51, 95%CI 0.29-0.87, p=0.015 before correction for multiple testing). After stratification by sex, association remained significant in females (OR=0.41, 95%CI 0.21-0.77, p=0.007), but not in males (OR=0.97, 95%CI 0.33-2.79, p=1). The finding was validated in a replication study (OR=0.66, 95%CI 0.48-0.90, p=0.011 for females). CNTNAP4 association with longevity was supported by a marked 25% lifespan change in C. elegans after knocking down the ortholog gene. An inverse association of the CNV del/del variant with female healthy aging was observed (OR=0.39, 95%CI 0.19-0.76, p=0.006). A corresponding positive association with aging-related diseases was revealed for cognitive impairment (OR=2.17, 95%CI 1.11-4.22, p=0.024) and, in independent studies, for Alzheimer's (OR=4.07, 95%CI 1.17-14.14, p=0.036) and Parkinson's (OR=1.59, 95%CI 1.03-2.42, p=0.041) diseases. CONCLUSION: This is the first demonstration for association of the CNTNAP4 gene and one of its intronic CNV polymorphisms with aging. Association with particular aging-related diseases awaits replication and independent validation.


Subject(s)
Aging/genetics , DNA Copy Number Variations/genetics , Nerve Tissue Proteins/genetics , Aged, 80 and over , Aging/physiology , Female , Genome-Wide Association Study , Humans , Longevity/genetics , Male , Models, Theoretical
12.
J Vis Exp ; (75): e50435, 2013 May 17.
Article in English | MEDLINE | ID: mdl-23711592

ABSTRACT

Amylopathy is a term that describes abnormal synthesis and accumulation of amyloid beta (Aß) in tissues with time. Aß is a hallmark of Alzheimer's disease (AD) and is found in Lewy body dementia, inclusion body myositis and cerebral amyloid angiopathy (1-4). Amylopathies progressively develop with time. For this reason simple organisms with short lifespans may help to elucidate molecular aspects of these conditions. Here, we describe experimental protocols to study Aß-mediated neurodegeneration using the worm Caenorhabditis elegans. Thus, we construct transgenic worms by injecting DNA encoding human Aß42 into the syncytial gonads of adult hermaphrodites. Transformant lines are stabilized by a mutagenesis-induced integration. Nematodes are age synchronized by collecting and seeding their eggs. The function of neurons expressing Aß42 is tested in opportune behavioral assays (chemotaxis assays). Primary neuronal cultures obtained from embryos are used to complement behavioral data and to test the neuroprotective effects of anti-apoptotic compounds.


Subject(s)
Amyloid beta-Peptides/biosynthesis , Amyloid beta-Peptides/genetics , Caenorhabditis elegans/genetics , Caenorhabditis elegans/metabolism , Disease Models, Animal , Peptide Fragments/biosynthesis , Peptide Fragments/genetics , Alzheimer Disease/metabolism , Alzheimer Disease/pathology , Animals , Animals, Genetically Modified , Humans , Neurodegenerative Diseases/pathology , Neurons/metabolism , Neurons/pathology
13.
Autophagy ; 9(4): 538-49, 2013 Apr.
Article in English | MEDLINE | ID: mdl-23380892

ABSTRACT

Autophagy is a highly conserved process that maintains intracellular homeostasis by degrading proteins or organelles in all eukaryotes. The effect of autophagy on fungal biology and infection of insect pathogens is unknown. Here, we report the function of MrATG8, an ortholog of yeast ATG8, in the entomopathogenic fungus Metarhizium robertsii. MrATG8 can complement an ATG8-defective yeast strain and deletion of MrATG8 impaired autophagy, conidiation and fungal infection biology in M. robertsii. Compared with the wild-type and gene-rescued mutant, Mratg8Δ is not inductive to form the infection-structure appressorium and is impaired in defense response against insect immunity. In addition, accumulation of lipid droplets (LDs) is significantly reduced in the conidia of Mratg8Δ and the pathogenicity of the mutant is drastically impaired. We also found that the cellular level of a LD-specific perilipin-like protein is significantly lowered by deletion of MrATG8 and that the carboxyl terminus beyond the predicted protease cleavage site is dispensable for MrAtg8 function. To corroborate the role of autophagy in fungal physiology, the homologous genes of yeast ATG1, ATG4 and ATG15, designated as MrATG1, MrATG4 and MrATG15, were also deleted in M. robertsii. In contrast to Mratg8Δ, these mutants could form appressoria, however, the LD accumulation and virulence were also considerably impaired in the mutant strains. Our data showed that autophagy is required in M. robertsii for fungal differentiation, lipid biogenesis and insect infection. The results advance our understanding of autophagic process in fungi and provide evidence to connect autophagy with lipid metabolism.


Subject(s)
Autophagy , Lipid Metabolism , Metarhizium/growth & development , Metarhizium/pathogenicity , Amino Acid Sequence , Animals , Autophagy/genetics , Bombyx/microbiology , Evolution, Molecular , Fungal Proteins/chemistry , Fungal Proteins/genetics , Fungal Proteins/metabolism , Gene Deletion , Gene Expression Regulation, Fungal , Genes, Fungal/genetics , Glycine/metabolism , Metarhizium/cytology , Metarhizium/genetics , Molecular Sequence Data , Mutagenesis/genetics , Phenotype , Spores, Fungal/cytology , Spores, Fungal/growth & development , Spores, Fungal/ultrastructure , Transcription, Genetic , Virulence
14.
FASEB J ; 27(4): 1381-93, 2013 Apr.
Article in English | MEDLINE | ID: mdl-23233530

ABSTRACT

Voltage-gated K(+) channels of the Shaw family (also known as the KCNC or Kv3 family) play pivotal roles in mammalian brains, and genetic or pharmacological disruption of their activities in mice results in a spectrum of behavioral defects. We have used the model system of Caenorhabditis elegans to elucidate conserved molecular mechanisms that regulate these channels. We have now found that the C. elegans Shaw channel KHT-1, and its mammalian homologue, murine Kv3.1b, are both modulated by acid phosphatases. Thus, the C. elegans phosphatase ACP-2 is stably associated with KHT-1, while its mammalian homolog, prostatic acid phosphatase (PAP; also known as ACPP-201) stably associates with murine Kv3.1b K(+) channels in vitro and in vivo. In biochemical experiments both phosphatases were able to reverse phosphorylation of their associated channel. The effect of phosphorylation on both channels is to produce a decrease in current amplitude and electrophysiological analyses demonstrated that dephosphorylation reversed the effects of phosphorylation on the magnitude of the macroscopic currents. ACP-2 and KHT-1 were colocalized in the nervous system of C. elegans and, in the mouse nervous system, PAP and Kv3.1b were colocalized in subsets of neurons, including in the brain stem and the ventricular zone. Taken together, this body of evidence suggests that acid phosphatases are general regulatory partners of Shaw-like K(+) channels.


Subject(s)
Brain Stem/metabolism , Evolution, Molecular , Neurons/metabolism , Shaw Potassium Channels/genetics , Shaw Potassium Channels/metabolism , Animals , Brain Stem/pathology , Caenorhabditis elegans , Membrane Potentials/genetics , Mice , Mice, Inbred C57BL , Phosphorylation/physiology
15.
J Invertebr Pathol ; 109(1): 105-9, 2012 Jan.
Article in English | MEDLINE | ID: mdl-22024554

ABSTRACT

Insect pathogenic fungi like Beauveria bassiana have been developed as environmentally friendly biocontrol agents against arthropod pests. However, restrictive environmental factors, including solar ultraviolet (UV) radiation frequently lead to inconsistent field performance. To improve resistance to UV damage, we used Agrobacterium-mediated transformation to engineer B. bassiana with an exogenous tyrosinase gene. The results showed that the mitotically stable transformants produced larger amounts of yellowish pigments than the wild-type strain, and these imparted significantly increased UV-resistance. The virulence of the transgenic isolate was also significantly increased against the silkworm Bombyx mori and the mealworm Tenebrio molitor. This study demonstrated that genetic engineering of B. bassiana with a tyrosinase gene is an effective way to improve fungal tolerance against UV damage.


Subject(s)
Beauveria , Genetic Engineering/methods , Monophenol Monooxygenase/genetics , Pest Control, Biological/methods , Radiation Tolerance/genetics , Animals , Beauveria/enzymology , Beauveria/pathogenicity , Beauveria/radiation effects , Bombyx/microbiology , Host-Pathogen Interactions , Monophenol Monooxygenase/metabolism , Sunlight , Tenebrio/microbiology , Ultraviolet Rays , Virulence/genetics
16.
PLoS Genet ; 7(1): e1001264, 2011 Jan 06.
Article in English | MEDLINE | ID: mdl-21253567

ABSTRACT

Metarhizium spp. are being used as environmentally friendly alternatives to chemical insecticides, as model systems for studying insect-fungus interactions, and as a resource of genes for biotechnology. We present a comparative analysis of the genome sequences of the broad-spectrum insect pathogen Metarhizium anisopliae and the acridid-specific M. acridum. Whole-genome analyses indicate that the genome structures of these two species are highly syntenic and suggest that the genus Metarhizium evolved from plant endophytes or pathogens. Both M. anisopliae and M. acridum have a strikingly larger proportion of genes encoding secreted proteins than other fungi, while ~30% of these have no functionally characterized homologs, suggesting hitherto unsuspected interactions between fungal pathogens and insects. The analysis of transposase genes provided evidence of repeat-induced point mutations occurring in M. acridum but not in M. anisopliae. With the help of pathogen-host interaction gene database, ~16% of Metarhizium genes were identified that are similar to experimentally verified genes involved in pathogenicity in other fungi, particularly plant pathogens. However, relative to M. acridum, M. anisopliae has evolved with many expanded gene families of proteases, chitinases, cytochrome P450s, polyketide synthases, and nonribosomal peptide synthetases for cuticle-degradation, detoxification, and toxin biosynthesis that may facilitate its ability to adapt to heterogeneous environments. Transcriptional analysis of both fungi during early infection processes provided further insights into the genes and pathways involved in infectivity and specificity. Of particular note, M. acridum transcribed distinct G-protein coupled receptors on cuticles from locusts (the natural hosts) and cockroaches, whereas M. anisopliae transcribed the same receptor on both hosts. This study will facilitate the identification of virulence genes and the development of improved biocontrol strains with customized properties.


Subject(s)
Genome, Fungal , Metarhizium/genetics , Animals , Base Sequence , Cockroaches/microbiology , Fungal Proteins/genetics , Fungal Proteins/metabolism , Gene Expression Profiling , Metarhizium/metabolism , Phylogeny , Signal Transduction
17.
Environ Microbiol ; 11(9): 2351-60, 2009 Sep.
Article in English | MEDLINE | ID: mdl-19538505

ABSTRACT

Pentose metabolism through the phosphoketolase pathway has been well characterized in bacteria. In this paper, we report the identification of a phosphoketolase homologue Mpk1 in the insect-pathogenic fungus Metarhizium anisopliae. Phylogenetic analysis showed that fungal phosphoketolases are of bacterial origin and diverged into two superfamilies. Frequent gene loss or lack of acquisition is evident in specific fungal lineages or species. The mpk1 gene is highly expressed when grown in trehalose-rich insect haemolymph but poorly induced by insect cuticle or carbohydrate-rich plant root exudate. In addition, mpk1 gene expression and enzyme activity could be upregulated by different sugars including xylose, trehalose, glucose or sucrose. mpk1 null mutants generated by homologous recombination grew similar to the wild type of M. anisopliae on medium amended with xylose as a sole carbon source. However, insect (tobacco hornworm, Manduca sexta) bioassays showed significantly reduced virulence in Deltampk1. The results of this study suggest that the horizontally transferred Mpk1 in M. anisopliae plays an important niche adaptation role for fungal propagation in insect haemocoel. Following the carbohydrate flux from plants to plant-feeding insects and insect pathogenic fungi, a tritrophic relationship is discussed in association with the requirement of fungal phosphoketolase pathway.


Subject(s)
Aldehyde-Lyases/genetics , Gene Transfer, Horizontal , Metarhizium/pathogenicity , Virulence Factors/genetics , Adaptation, Physiological , Aldehyde-Lyases/metabolism , Animals , Base Sequence , Gene Expression Profiling , Gene Expression Regulation, Fungal , Genes, Bacterial , Host-Pathogen Interactions , Insecta/microbiology , Manduca/pathogenicity , Metarhizium/enzymology , Molecular Sequence Data , Pentose Phosphate Pathway , Pentoses/metabolism , Phylogeny , Virulence Factors/metabolism
18.
Eukaryot Cell ; 7(2): 302-9, 2008 Feb.
Article in English | MEDLINE | ID: mdl-18055914

ABSTRACT

Entomopathogenic fungi such as Metarhizium anisopliae infect insects by direct penetration of the cuticle, after which the fungus adapts to the high osmotic pressure of the hemolymph and multiplies. Here we characterize the M. anisopliae Mos1 gene and demonstrate that it encodes the osmosensor required for this process. MOS1 contains transmembrane regions and a C-terminal Src homology 3 domain similar to those of yeast osmotic adaptor proteins, and homologs of MOS1 are widely distributed in the fungal kingdom. Reverse transcription-PCR demonstrated that Mos1 is up-regulated in insect hemolymph as well as artificial media with high osmotic pressure. Transformants containing an antisense vector directed to the Mos1 mRNA depleted transcript levels by 80%. This produced selective alterations in regulation of genes involved in hyphal body formation, cell membrane stiffness, and generation of intracellular turgor pressure, suggesting that these processes are mediated by MOS1. Consistent with a role in stress responses, transcript depletion of Mos1 increased sensitivity to osmotic and oxidative stresses and to compounds that interfere with cell wall biosynthesis. It also disrupted developmental processes, including formation of appressoria and hyphal bodies. Insect bioassays confirmed that Mos1 knockdown significantly reduces virulence. Overall, our data show that M. anisopliae MOS1 mediates cellular responses to high osmotic pressure and subsequent adaptations to colonize host hemolymph.


Subject(s)
Adaptation, Physiological , Genes, mos/physiology , Hemolymph/immunology , Manduca/growth & development , Metarhizium/metabolism , Metarhizium/pathogenicity , Oxidative Stress , Animals , Cell Differentiation , Cell Proliferation , Cloning, Molecular , Fungal Proteins , Gene Expression Regulation, Fungal , Hemolymph/microbiology , Host-Parasite Interactions , Manduca/microbiology , Osmolar Concentration , Osmotic Pressure , Phylogeny , Reverse Transcriptase Polymerase Chain Reaction , Virulence/physiology
19.
J Zhejiang Univ Sci B ; 8(9): 661-5, 2007 Sep.
Article in English | MEDLINE | ID: mdl-17726747

ABSTRACT

The promoter of NAR gene in Magnaporthe grisea was isolated and sequenced. The promoter sequences contained the "TATA" box, the "CAAT" box, and binding sites for fungal regulatory proteins. Programs that predict promoter sequences indicated that promoter sequence lies between locations 430 and 857 of the NAR promoter fragment. GFP expression under the NAR promoter and NAR transcript analysis revealed that this promoter is activated primarily at the mycelial stage in the rice blast fungus and could be used to express native or extrinsic genes in the mycelia of the rice blast fungus.


Subject(s)
Fungal Proteins/genetics , Gene Expression/genetics , Hyphae/genetics , Magnaporthe/genetics , Promoter Regions, Genetic/genetics , Transcriptional Activation/genetics , Base Sequence , Cloning, Molecular , Molecular Sequence Data
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