Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 15 de 15
Filter
Add more filters










Publication year range
1.
Langmuir ; 40(24): 12419-12426, 2024 Jun 18.
Article in English | MEDLINE | ID: mdl-38836381

ABSTRACT

Recently, polyurethane elastomer (TPU) has attracted more and more attention depending on its excellent optical, mechanical, and retreatment properties. The high strength of polyurethane has always been pursued, which can enable its application in more fields. In this work, an aliphatic polyurethane elastomer membrane (HRPU6) was successfully synthesized, and its strength was obviously improved by solvent annealing technology. The tensile strength and adhesion strength can reach 64.56 and 2.58 MPa, but 36.55 and 1.57 MPa only before solvent annealing, respectively. The impact strength of laminated glass based on HRPU has also been significantly improved after solvent annealing, confirmed through drop ball impact testing. It has been confirmed that the increase in strength of HRPU6 is attributed to the enhancement of hydrogen bonding and the improvement of the phase separation degree.

2.
Front Pediatr ; 11: 1155481, 2023.
Article in English | MEDLINE | ID: mdl-37033185

ABSTRACT

Introduction: Leukapheresis reduces hyperleukocytosis in children with acute leukemia. Although the usefulness of this procedure is under debate, a repeated small-volume exchange transfusion along with leukapheresis yielded satisfactory results. Methods: Forty-seven patients with acute leukemia [32 acute lymphocytic leukemia (ALL) and 15 acute myeloblastic leukemia (AML)] were enrolled between January 2017 and June 2022 and underwent repeated small-volume exchange transfusion. The following were measured: demographic and clinical characteristics, time of the procedure, PWBC (peripheral white blood cell) count, hemoglobin, platelet count, blood biochemistry, electrolytes, coagulation, leukostasis, TLS (tumor lysis syndrome), DIC (disseminated intravascular coagulopathy), adverse events (AEs), and serious AEs (SAEs). Results: The demographic and clinical characteristics were not significantly different between ALL and AML patients, but differences were observed in PWBC counts (424.2 ± 135.6 vs. 223.8 ± 58.0 × 109/L). The procedures needed 3-8 processes, and the average procedure time was not significantly different between ALL and AML. The PWBC count gradually reduced to <100 × 109/L; hemoglobin, platelet count, K+, Na+, and Ca2+ were unchanged. Alanine aminotransferase, aspartate aminotransferase, total bilirubin, blood urea nitrogen, creatinine, troponin-I, creatine kinase-MB, prothrombin time, and activated partial thromboplastin time maintained normal or recovered from abnormal ranges. The manifestations of leukostasis, TLS, and DIC improved or disappeared. No AEs and SAEs occurred. The required total blood volume was based on initial PWBC count, manifestations of leukostasis, and age. Conclusions: Our finding suggests that repeated small-volume exchange transfusion is effective and safe for treating hyperleukocytosis in children with acute leukemia.

3.
J Colloid Interface Sci ; 587: 550-560, 2021 Apr.
Article in English | MEDLINE | ID: mdl-33220954

ABSTRACT

Biomimetic construction of artificial photosystem capable of converting light energy to chemical energy is a promising strategy in solving the increasing serious energy and environmental problems. Herein, we present a new strategy to construct light-harvesting antenna via hierarchical co-assembly of short-peptide and porphyrin and subsequent self-metallization process. The hierarchically organized antenna exhibits both excellent photocatalytic performance and remarkable sustainability under strong light irradiation (35000 lx) and extraordinary sensitivity to weak light (700 lx). In such cases, light energy can be converted into chemical energy and stored in the energy-storage molecules (nicotinamide adenine dinucleotide, NADH) even under weak light irradiation. This provides a promising step towards an artificial photosystem that can utilize weak light. Moreover, the structures and properties of the antenna are dependent on the competition of short-peptide self-assembling and co-assembling with porphyrin molecules and can be regulated by their molar ratio. This provides new insights into the design and construction of light-harvesting antennas with integrated functionality via precise control of pigments aggregation and coupling of different functional units.

4.
Support Care Cancer ; 28(10): 4721-4727, 2020 Oct.
Article in English | MEDLINE | ID: mdl-31970512

ABSTRACT

OBJECTIVES: In this study, Problem Management Plus (PM+) was used for patients with multiple myeloma (MM), to develop a care model of psychology and quality of life. METHODS: Forty cases received psychological management (PM+ group), and 40 cases underwent investigation without management (non-PM+ group). Patients were assessed using PSYCHLOPS, WHO DAS 2.0, and HADS (see Supplementary File 1). RESULTS: The results showed that the PM+ group showed reductions in Psychological Outcome Profile scores (6.3 ± 2.9) following program completion (preprogram scores: 16.0 ± 1.9, P < .05). The non-PM+ group showed differences between preprogram (16.7 ± 1.8) and postprogram scores (14.8 ± 2.6, P < .05). The effect size of the PM+ group exceeded that of the non-PM+ group (5.1 to 1.0). In the Hospital Anxiety and Depression Scale, the PM+ group showed reductions in anxiety (6.4 ± 1.8) and depression (5.4 ± 0.7) (preprogram scores: 14.7 ± 4.3, P < .05 and 10.9 ± 2.6, P < .05, respectively). In the Hospital Anxiety and Depression Scale, scores for mobility, self-care, getting along, life activities, and participation decreased in the PM+ group following program completion (all P's < .05) but did not decrease in the non-PM+ group (all P > .05). CONCLUSION: The PM+ strategy could help patients to alleviate symptoms of anxiety and depression and strengthen social support, to aid in the management of problems and improve mental disorders. IMPACT STATEMENT: MM patients often experienced mental disorders and wished to participate in psychosocial interventions; the PM+ strategies should be as a wide to help patients manage their problems and alleviate the symptoms of anxiety and depression.


Subject(s)
Anxiety/therapy , Depression/therapy , Multiple Myeloma/psychology , Psychotherapy/methods , Anxiety/diagnosis , Anxiety/etiology , Depression/diagnosis , Depression/etiology , Depression/psychology , Female , Humans , Male , Middle Aged , Models, Psychological , Quality of Life , Social Support
5.
PLoS One ; 14(6): e0218605, 2019.
Article in English | MEDLINE | ID: mdl-31233537

ABSTRACT

The integration of conflicting signals in response to environmental constraints is essential to efficient plant growth and development. The light-dependent and the stress hormone abscisic acid (ABA)-dependent signaling pathways play opposite roles in many aspects of plant development. While these pathways have been extensively studied, the complex nature of their molecular dialogue is still obscure. When mobilized by the Arabidopsis thaliana ß-glucosidase 1 (AtBG1), the glucose ester-conjugated inactive form of ABA has proven to be a source of the active hormone that is essential for the adaptation of the plant to water deficit, as evidenced by the impaired stomatal closure of atbg1 mutants in response to water stress. In a suppressor screen designed to identify the molecular components of AtBG1-associated physiological and developmental mechanisms, we identified the mutation variant of AtBG1 traits (vat1), a new mutant allele of the red light/far-red light photoreceptor PHYTOCHROME B (PHYB). Our study reveals that atbg1 plants harbor increased stomatal density in addition to impaired stomatal closure. We also provide evidence that the vat1/phyb mutation can restore the apparent transpiration of the atbg1 mutant by decreasing stomatal aperture and restoring a stomatal density similar to wild-type plants. Expression of key regulators of stomatal development showed a crosstalk between AtBG1-mediated ABA signaling and PHYB-mediated stomatal development. We conclude that the AtBG1-dependent regulation of ABA homeostasis and the PHYB-mediated light signaling pathways act antagonistically in the control of stomatal development.


Subject(s)
Arabidopsis Proteins/metabolism , Arabidopsis/metabolism , Phytochrome B/metabolism , beta-Glucosidase/metabolism , Abscisic Acid/analogs & derivatives , Abscisic Acid/metabolism , Acclimatization/genetics , Acclimatization/physiology , Amino Acid Sequence , Arabidopsis/genetics , Arabidopsis/growth & development , Arabidopsis Proteins/chemistry , Arabidopsis Proteins/genetics , Droughts , Gene Expression Regulation, Developmental , Gene Expression Regulation, Plant , Genes, Plant , Light , Models, Molecular , Mutation , Phytochrome B/chemistry , Phytochrome B/genetics , Plant Stomata/growth & development , Plant Stomata/metabolism , Protein Domains , Sequence Homology, Amino Acid , Signal Transduction , beta-Glucosidase/genetics
6.
Virology ; 528: 1-6, 2019 02.
Article in English | MEDLINE | ID: mdl-30550975

ABSTRACT

Horizontal transmission of virulence attenuating hypoviruses of Cryphonectria parasitica is restricted by an allorecognition system termed vegetative incompatibility (vic). A super donor formulation of two engineered C. parasitica strains (SD328/SD82) with gene disruptions at four of six vic loci transmitted hypovirus to strains in the laboratory independent of vic genotype. We now report the transmission of hypovirus by the SD328/82 formulation to a diverse, natural C. parasitica population infecting American chestnut in a forest setting. Hypovirulent (HV) isolates were recovered from 94% of cankers treated with the hypovirus-infected SD328/82 formulation compared to 51% of cankers treated with a hypovirus-infected EU5/6 formulation (strains having the same vic genotypes as SD strains but lacking vic gene disruptions). Overall, the SD328/82 formulation transmitted hypovirus into more divergent vic genotypes compared to the EU5/6 formulation. These results demonstrate the SD328/82 formulation can serve as an enhanced hypovirus vector for highly divergent C. parasitica populations.


Subject(s)
Ascomycota/virology , Biological Control Agents , Fagaceae/microbiology , Plant Diseases/microbiology , RNA Viruses/genetics , Genotype , Virulence
7.
Appl Nurs Res ; 32: e1-e5, 2016 11.
Article in English | MEDLINE | ID: mdl-27595414

ABSTRACT

PURPOSE: To evaluate a nurse-led management model of adolescent acute lymphoblastic leukemia (ALL) patients and improve their psychological care and quality of life. METHODS: Seventy-three adolescent ALL patients participated in an open, controlled clinical trial and were randomized into a nurse-led management model group (n=36) and a doctor-led management model group (n=37). Two assessment questionnaires were administered to assess and compare the 2 models during a 1.5-year follow-up period: the hospital anxiety and depression scale (HADS) questionnaire was administered at 6 different time points, and the European Organization for Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire Core 30 (QLQ-C30) at 3 different time points. RESULTS: There were no differences in anxiety and depression between the groups according to the first-administered questionnaire (the mean anxiety and depression scores of the nurse-led group were 14.2±4.1 and 10.8±2.7, respectively; those of the doctor-led group were 13.8±3.8 and 10.6±2.2, respectively). However, repeated measures analysis of variance detected differences in subsequent HADS-based scores as a function of time between the 2 groups (p<0.05). Moreover, the Holm-Sidak's multiple comparisons tests showed that patients of the nurse-led group had significantly decreased mean anxiety scores compared to those in the doctor-led group at the third and subsequent sessions, as well as in mean depression scores from the second session onwards (all p<0.05). According to the last-administered EORTC QLQ-C30 questionnaire, there were statistical differences in cognitive, emotional, social, and quality of life scales between the 2 groups (all p<0.05), but not in role and physical scales (all p>0.05). CONCLUSIONS: It is necessary to offer unique cognitive, psychological, and behavioral management models to adolescent ALL patients that are tailored toward their age group. Strengthening such management is more conducive to alleviating or even reversing psychological problems, and to improving patients' quality of life while ensuring complication-free follow-up periods.


Subject(s)
Nursing Staff , Precursor Cell Lymphoblastic Leukemia-Lymphoma/nursing , Precursor Cell Lymphoblastic Leukemia-Lymphoma/therapy , Adolescent , Female , Humans , Male , Precursor Cell Lymphoblastic Leukemia-Lymphoma/physiopathology , Precursor Cell Lymphoblastic Leukemia-Lymphoma/psychology , Quality of Life , Surveys and Questionnaires
8.
Proc Natl Acad Sci U S A ; 113(8): 2062-7, 2016 Feb 23.
Article in English | MEDLINE | ID: mdl-26858412

ABSTRACT

Transmission of mycoviruses that attenuate virulence (hypovirulence) of pathogenic fungi is restricted by allorecognition systems operating in their fungal hosts. We report the use of systematic molecular gene disruption and classical genetics for engineering fungal hosts with superior virus transmission capabilities. Four of five diallelic virus-restricting allorecognition [vegetative incompatibility (vic)] loci were disrupted in the chestnut blight fungus Cryphonectria parasitica using an adapted Cre-loxP recombination system that allowed excision and recycling of selectable marker genes (SMGs). SMG-free, quadruple vic mutant strains representing both allelic backgrounds of the remaining vic locus were then produced through mating. In combination, these super donor strains were able to transmit hypoviruses to strains that were heteroallelic at one or all of the virus-restricting vic loci. These results demonstrate the feasibility of modulating allorecognition to engineer pathogenic fungi for more efficient transmission of virulence-attenuating mycoviruses and enhanced biological control potential.


Subject(s)
Fungal Viruses , Genetic Engineering , Genetic Loci , Sordariales , Aesculus/microbiology , Fungal Viruses/genetics , Fungal Viruses/metabolism , Fungal Viruses/pathogenicity , Plant Diseases/microbiology , Sordariales/genetics , Sordariales/metabolism , Sordariales/virology
9.
PLoS One ; 9(9): e108653, 2014.
Article in English | MEDLINE | ID: mdl-25268858

ABSTRACT

An inducible RNA-silencing pathway, involving a single Dicer protein, DCL2, and a single Argonaute protein, AGL2, was recently shown to serve as an effective antiviral defense response in the chestnut blight fungus Cryphonectria parasitica. Eukaryotic RNA-dependent RNA polymerases (RdRPs) are frequently involved in transcriptional and posttranscriptional gene silencing and antiviral defense. We report here the identification and characterization of four RdRP genes (rdr1-4) in the C. parasitica genome. Sequence relationships with other eukaryotic RdRPs indicated that RDR1 and RDR2 were closely related to QDE-1, an RdRP involved in RNA silencing ("quelling") in Neurospora crassa, whereas RDR3 was more closely related to the meiotic silencing gene SAD-1 in N. crassa. The RdRP domain of RDR4, related to N. crassa RRP-3 of unknown function, was truncated and showed evidence of alternative splicing. Similar to reports for dcl2 and agl2, the expression levels for rdr3 and rdr4 increased after hypovirus CHV-1/EP713 infection, while expression levels of rdr1 and rdr2 were unchanged. The virus-responsive induction patterns for rdr3 and rdr4 were altered in the Δdcl2 and Δagl2 strains, suggesting some level of interaction between rdr3 and rdr4 and the dcl2/agl2 silencing pathway. Single rdr gene knockouts Δrdr1-4, double knockouts Δrdr1/2, Δrdr2/3, Δrdr1/3, and a triple knockout, Δrdr1/2/3, were generated and evaluated for effects on fungal phenotype, the antiviral defense response, viral RNA recombination activity and transposon expression. None of the single or multiple rdr knockout strains displayed any phenotypic differences from the parental strains with or without viral infection or any significant changes in viral RNA accumulation or recombination activity or transposon RNA accumulation, indicating no detectable contribution by the C. parasitica rdr genes to these processes.


Subject(s)
Ascomycota/genetics , Gene Expression Regulation, Fungal , Genes, Fungal , Genome, Fungal , RNA-Dependent RNA Polymerase/genetics , Repressor Proteins/genetics , Amino Acid Sequence , Ascomycota/immunology , Ascomycota/virology , DNA Transposable Elements , Gene Silencing , Host-Pathogen Interactions , Molecular Sequence Data , Protein Isoforms/genetics , Protein Isoforms/immunology , RNA Viruses/genetics , RNA-Dependent RNA Polymerase/immunology , Recombination, Genetic , Repressor Proteins/immunology , Sequence Alignment , Transcription, Genetic
10.
Genetics ; 197(2): 701-14, 2014 Jun.
Article in English | MEDLINE | ID: mdl-24690544

ABSTRACT

Vegetative incompatibility (vic), a form of nonself allorecognition, operates widely in filamentous fungi and restricts transmission of virulence-attenuating hypoviruses in the chestnut blight fungus Cryphonectria parasitica. We report here the use of a polymorphism-based comparative genomics approach to complete the molecular identification of the genetically defined C. parasitica vic loci with the identification of vic1 and vic3. The vic1 locus in the C. parasitica reference strain EP155 consists of a polymorphic HET-domain-containing 771-aa ORF designated vic1a-2, which shares 91% identity with the corresponding vic1a-1 allele, and a small (172 aa) idiomorphic DUF1909-domain-containing ORF designated vic1b-2 that is absent at the vic1-1 locus. Gene disruption of either vic1a-2 or vic1b-2 in strain EP155 eliminated restrictions on virus transmission when paired with a vic1 heteroallelic strain; however, only disruption of vic1a-2 abolished the incompatible programmed cell death (PCD) reaction. The vic3 locus of strain EP155 contains two polymorphic ORFs of 599 aa (vic3a-1) and 102 aa (vic3b-1) that shared 46 and 85% aa identity with the corresponding vic3a-2 and vic3b-2 alleles, respectively. Disruption of either vic3a-1 or vic3b-1 resulted in increased virus transmission. However, elimination of PCD required disruption of both vic3a and vic3b. Additional allelic heterogeneity included a sequence inversion and a 8.5-kb insertion containing a LTR retrotransposon sequence and an adjacent HET-domain gene at the vic1 locus and a 7.7-kb sequence deletion associated with a nonfunctional, pseudo vic locus. Combined gene disruption studies formally confirmed restriction of mycovirus transmission by five C. parasitica vic loci and suggested dedicated roles in allorecognition. The relevance of these results to the acquisition and maintenance of vic genes and the potential for manipulation of vic alleles for enhanced mycovirus transmission are discussed.


Subject(s)
Ascomycota/genetics , Ascomycota/virology , Genetic Loci , RNA Viruses/physiology , Cell Death , Gene Deletion , Genes, Fungal , Genomics , Mycelium/growth & development
11.
Fungal Genet Biol ; 61: 1-8, 2013 Dec.
Article in English | MEDLINE | ID: mdl-24007936

ABSTRACT

Reverse-genetics analysis has played a significant role in advancing fungal biology, but is limited by the number of available selectable marker genes (SMGs). The Cre-loxP recombination system has been adapted for use in filamentous fungi to overcome this limitation. Expression of the Cre recombinase results in excision of an integrated SMG that is flanked by loxP sites, allowing a subsequent round of transformation with the same SMG. However, current protocols for regulated expression or presentation of Cre require multiple time-consuming steps. During efforts to disrupt four different RNA-dependent RNA polymerase genes in a single strain of the chestnut blight fungus Cryphonectria parasitica, we tested whether Cre could successfully excise loxP-flanked SMGs when provided in trans via anastomosis. Stable Cre-producing donor strains were constructed by transformation of wild-type C. parasitica strain EP155 with the Cre-coding domain under the control of a constitutive promoter. Excision of multiple loxP-flanked SMGs was efficiently achieved by simply pairing the Cre-donor strain and the loxP-flanked SMGs-transformed recipient strain and recovering mycelia from the margin of the recipient colony near the anastomosis zone. This method was shown to be as efficient as and much less time consuming than excision by transformation-mediated expression of Cre. It also allows unlimited recycling of loxP-flanked SMGs and the generation of disruption mutant strains that are free of any foreign gene. The successful application of this method to Metarhizium robertsii suggests potential use for optimizing reverse-genetics analysis in a broad range of filamentous fungi.


Subject(s)
Ascomycota/genetics , Genes, Fungal , Genetics, Microbial/methods , Reverse Genetics/methods , Selection, Genetic , Gene Deletion , Recombination, Genetic , Transformation, Genetic
12.
Plant Signal Behav ; 5(11): 1419-22, 2010 Nov.
Article in English | MEDLINE | ID: mdl-21051952

ABSTRACT

Many cool-season grasses (Poaceae, subfam. Pooideae) possess seedborne fungal symbionts, the epichloae, known for their bioprotective properties, and especially for production of anti-insect alkaloids such as lolines. Asexual epichloae (Neotyphodium species) are primarily or entirely transmitted vertically, whereas the sexual structures (stromata) of the related Epichloë species give rise to horizontally transmissible spores (ascospores). In certain grass-Neotyphodium species symbiota, levels of lolines are extremely high and apparently limited by availability of precursor amino acids, whereas sexual epichloae generally produce much lower levels. This may reflect the inherent conflict between the vertical and horizontal transmission; although the plant and seeds may be protected by the alkaloids, the sexual cycle depends on anthomyiid flies for cross-fertilization. Given this insect role, we predicted that loline biosynthesis would be down-regulated in the stromata relative to the corresponding asymptomatic tissues (inflorescences) of the same symbiota. This prediction was substantiated, and RNA-seq and RT-qPCR analysis indicated that the loline biosynthesis genes are dramatically upregulated in asymptomatic inflorescences compared to stromata. The fundamental difference between asexual and sexual epichloae in regulation of loline alkaloid levels is in keeping with evolutionary trends for greater host control on metabolism of their vertically transmitted symbionts compared to contagious symbionts.


Subject(s)
Alkaloids/chemistry , Alkaloids/metabolism , Gene Expression Regulation, Fungal/physiology , Neotyphodium/metabolism , Poaceae/microbiology , Amino Acids/metabolism , Seeds/microbiology , Spores, Fungal
13.
Plant Physiol ; 150(2): 1072-82, 2009 Jun.
Article in English | MEDLINE | ID: mdl-19403726

ABSTRACT

Neotyphodium uncinatum and Neotyphodium siegelii are fungal symbionts (endophytes) of meadow fescue (MF; Lolium pratense), which they protect from insects by producing loline alkaloids. High levels of lolines are produced following insect damage or mock herbivory (clipping). Although loline alkaloid levels were greatly elevated in regrowth after clipping, loline-alkaloid biosynthesis (LOL) gene expression in regrowth and basal tissues was similar to unclipped controls. The dramatic increase of lolines in regrowth reflected the much higher concentrations in young (center) versus older (outer) leaf blades, so LOL gene expression was compared in these tissues. In MF-N. siegelii, LOL gene expression was similar in younger and older leaf blades, whereas expression of N. uncinatum LOL genes and some associated biosynthesis genes was higher in younger than older leaf blades. Because lolines are derived from amino acids that are mobilized to new growth, we tested the amino acid levels in center and outer leaf blades. Younger leaf blades of aposymbiotic plants (no endophyte present) had significantly higher levels of asparagine and sometimes glutamine compared to older leaf blades. The amino acid levels were much lower in MF-N. siegelii and MF-N. uncinatum compared to aposymbiotic plants and MF with Epichloë festucae (a closely related symbiont), which lacked lolines. We conclude that loline alkaloid production in young tissue depleted these amino acid pools and was apparently regulated by availability of the amino acid substrates. As a result, lolines maximally protect young host tissues in a fashion similar to endogenous plant metabolites that conform to optimal defense theory.


Subject(s)
Alkaloids/metabolism , Feeding Behavior , Neotyphodium/physiology , Poaceae/microbiology , Symbiosis , Amino Acids/metabolism , Animals , Biomass , Gene Expression Regulation, Fungal , Insecta/physiology , Models, Biological , Molecular Sequence Data , Neotyphodium/genetics , Plant Leaves/metabolism , Plant Leaves/microbiology , Symbiosis/genetics , Water
14.
Fungal Genet Biol ; 46(8): 517-30, 2009 Aug.
Article in English | MEDLINE | ID: mdl-19366635

ABSTRACT

Epichloë endophytes (holomorphic Epichloë spp. and anamorphic Neotyphodium spp.) are systemic, often heritable symbionts of cool-season grasses (subfamily Pooideae). Many epichloae provide protection to their hosts by producing anti-insect compounds. Among these are the loline alkaloids (LA), which are toxic and deterrent to a broad range of herbivorous insects but not to mammalian herbivores. LOL, a gene cluster containing nine genes, is associated with LA biosynthesis. We investigated coordinate regulation between LOL-gene expression and LA production in minimal medium (MM) cultures of Neotyphodium uncinatum. Expression of all LOL genes significantly fit temporal quadratic patterns during LA production. LOL-gene expression started before LA were detectable, and increased while LA accumulated. The highest gene expression level was reached at close to the time of most rapid LA accumulation, and gene expression declined to a very low level as amounts of LA plateaued. Temporal expression profiles of the nine LOL genes were tightly correlated with each other, but not as tightly correlated with proC and metE (genes for biosynthesis of precursor amino acids). Furthermore, the start days and peak days of expression significantly correlated with the order of the LOL-cluster genes in the genome. Hierarchical cluster analysis indicated three pairs of genes-lolA and lolC, lolO and lolD, and lolT and lolE-expression of which was especially tightly correlated. Of these, lolA and lolC tended to be expressed early, and lolT and lolE tended to be expressed late, in keeping with the putative roles of the respective gene products in the LA-biosynthesis pathway. Several common transcriptional binding sites were discovered in the LOL upstream regions. However, low expression of P(lolC2)uidA and P(lolA2)uidA in N. uncinatum transformants suggested induced expression of LOL genes might be subject to position effect at the LOL locus.


Subject(s)
Alkaloids/biosynthesis , Biosynthetic Pathways/genetics , Fungal Proteins/biosynthesis , Gene Expression Regulation, Fungal , Neotyphodium/physiology , Binding Sites , DNA, Fungal/genetics , Fungal Proteins/genetics , Gene Expression Profiling , Neotyphodium/genetics , Poaceae/microbiology , Regulatory Elements, Transcriptional
15.
Fungal Genet Biol ; 45(9): 1307-14, 2008 Sep.
Article in English | MEDLINE | ID: mdl-18655839

ABSTRACT

The insecticidal loline alkaloids, produced by Neotyphodium uncinatum and related endophytes, are exo-1-aminopyrrolizidines with an ether bridge between C-2 and C-7. Loline alkaloids vary in methyl, acetyl, and formyl substituents on the 1-amine, which affect their biological activity. Enzymes for key loline biosynthesis steps are probably encoded by genes in the LOL cluster, which is duplicated in N. uncinatum, except for a large deletion in lolP2. The role of lolP1 was investigated by its replacement with a hygromycin B phosphotransferase gene. Compared to wild type N. uncinatum and an ectopic transformant, DeltalolP1 cultures had greatly elevated levels of N-methylloline (NML) and lacked N-formylloline (NFL). Complementation of DeltalolP1 with lolP1 under control of the Emericella nidulans trpC promoter restored NFL production. These results and the inferred sequence of LolP1 indicate that it is a cytochrome P450, catalyzing oxygenation of an N-methyl group in NML to the N-formyl group in NFL.


Subject(s)
Alkaloids/biosynthesis , Cytochrome P-450 Enzyme System/metabolism , Fungal Proteins/metabolism , Hypocreales/enzymology , Hypocreales/genetics , Alkaloids/chemistry , Cytochrome P-450 Enzyme System/genetics , Fungal Proteins/genetics , Hypocreales/chemistry , Hypocreales/metabolism , Protoplasts/metabolism
SELECTION OF CITATIONS
SEARCH DETAIL
...