scholarly journals Effects of Temperature, Humidity, and Wound Age on Valsa mali Infection of Apple Shoot Pruning Wounds

Plant Disease ◽  
2016 ◽  
Vol 100 (12) ◽  
pp. 2394-2401 ◽  
Author(s):  
Chong Chen ◽  
Bao-Hua Li ◽  
Xiang-Li Dong ◽  
Cai-Xia Wang ◽  
Sen Lian ◽  
...  
Keyword(s):  
Hyphal Growth ◽  
Wound Age ◽  
Protective Film ◽  
Critical Periods ◽  
Effective Measure ◽  
Valsa Canker ◽  
Effects Of Temperature ◽  
Valsa Mali

Valsa canker, caused by Valsa mali, is a destructive disease of apple in China. The pathogen infects apple branches, mainly through pruning wounds, and causes branch and tree death. To determine the conditions required for V. mali infection through pruning wounds and growth within the xylem, pruning wounds on 1- to 4-year-old apple branches were inoculated with conidia in vitro under artificially controlled conditions and in vivo in the orchard. The effects of temperature, wetness duration, and wound age on conidial infection through pruning wounds as well as hyphal growth in the xylem were examined. The results showed that, after invading through pruning wounds, V. mali hyphae grew along xylem vessels, tracheids, and rays, expanding longitudinally and laterally. The hyphae could enter adjacent xylem vessels and tracheids through micropores to form a dense hyphal network. Wetness duration did not exhibit an essential effect on conidial infection from pruning wounds. Conidia spread to pruning wounds with rainwater could infect the xylem without any other extra moisture. Temperature for V. mali conidia infection through pruning wounds and hyphal extension in the xylem ranged from 5 to 35°C, with the optimum at 20°C. Pruning wounds made in late March were susceptible to V. mali infection in March, April, and May; the susceptibility was markedly deceased by June, and the pathogen could barely infect through the pruning wounds in November. The infected pruning wounds began to show symptoms from the spring of the following year. More than half of the observed Valsa canker lesions emerged in the spring of the second year, and new canker twigs were also developed from the inoculations in the spring of the third year. March, April, and May are the critical periods for protecting pruning wounds against infection by V. mali in China, and coating pruning wounds with protective film immediately after pruning is an easy and effective measure to protect the pruning wounds.

scholarly journals Identification of the Putative Protein Phosphatase Gene PTC1 as a Virulence-Related Gene Using a Silkworm Model of Candida albicans Infection

2008 ◽  
Vol 7 (10) ◽  
pp. 1640-1648 ◽  
Author(s):  
Nozomu Hanaoka ◽  
Yukie Takano ◽  
Kazutoshi Shibuya ◽  
Hajime Fugo ◽  
Yoshimasa Uehara ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Mouse Model ◽  
Protein Phosphatase ◽  
Protein Phosphatases ◽  
Hyphal Growth ◽  
Marker Genes ◽  
Phenotypic Traits ◽  
Putative Protein

ABSTRACT Protein phosphatases are critical for the regulation of many cellular processes. Null mutants of 21 putative protein phosphatases of Candida albicans were constructed by consecutive allele replacement using the URA3 and ARG4 marker genes. A simple silkworm model of C. albicans infection was used to screen the panel of mutants. Four null mutant (cmp1Δ, yvh1Δ, sit4Δ, and ptc1Δ) strains showed attenuated virulence in the silkworm model relative to that of control and parental strains. Three of the mutants, the cmp1Δ, yvh1Δ, and sit4Δ mutants, had previously been identified as affecting virulence in a conventional mouse model, indicating the validity of the silkworm model screen. Disruption of the putative protein phosphatase gene PTC1 of C. albicans, which has 52% identity to the Saccharomyces cerevisiae type 2C protein phosphatase PTC1, significantly reduced virulence in the silkworm model. The mutant was also avirulent in a mouse model of disseminated candidiasis. Reintroducing either of the C. albicans PTC1 alleles into the disruptant strain, using a cassette containing either allele under the control of a constitutive ACT1 promoter, restored virulence in both infection models. Characterization of ptc1Δ revealed other phenotypic traits, including reduced hyphal growth in vitro and in vivo, and reduced extracellular proteolytic activity. We conclude that PTC1 may contribute to pathogenicity in C. albicans.

scholarly journals Morphologial variation in colonies of Chalara fraxinea isolated from ash (Fraxinus excelsior L.) stems with symptoms of dieback and effects of temperature on colony growth and structure

2012 ◽  
Vol 63 (1) ◽  
pp. 99-106 ◽  
Author(s):  
Tadeusz Kowalski ◽  
Czesław Bartnik
Keyword(s):  
Growth Rate ◽  
Colony Growth ◽  
Malt Extract ◽  
Optimum Temperature ◽  
Ash Trees ◽  
Effects Of Temperature ◽  
Main Factor

The present paper presents the results of long-term observations of differences in growth and morphology of colonies of <i>C. fraxinea</i> isolated from ash stems with symptoms of dieback and the results of studies on effects of temperature on growth and morphology of colonies <i>in vitro</i>. Thirty randomly chosen <i>C. fraxinea</i> cultures, originating from six Forest Districts in southern and northern Poland, viz. Andrychów, Gryfice, Kańczuga, Lębork, Miechów and Mircze, were included in the temperature assay. Colony growth and morphology were evaluated <i>in vitro</i>, on malt extract agar. Two replicates of each isolate were incubated at 5, 10, 15, 20, 25 and 30°C in darkness. Colonies of <i>C. fraxinea</i> isolated from necrotic stem tissues of diseased ash trees differed greatly in colour, structure, growth rate, presence of sectors and stromata as well as the intensity of conidial sporulation. Colony characters were often lost in further sub-cultures grown on the same medium. Colonies of <i>C. fraxinea</i> grew at 5-25°C <i>in vitro</i>. Three isolates still grew, though slowly, at 30°C. The optimum temperature for growth was 20°C. Among 30 isolates tested, five grew most quickly at 25°C and four at 15°C. Differences among colony diameters recorded at 5, 10, 15, 20 and 30°C were statistically significant, while differences at 15 and 25°C were not. At some temperatures, statistically significant differences in growth rate were related to the origin of the isolates. There were three main colony colour types. Temperature was the main factor affecting colony morphology <i>in vitro</i>. The formation of sectors was observed in 36% of colonies, pseudoparenchymatous stromata in 10.4% of colonies, and white crystalline substances in 53.3% of colonies. The results of <i>in vitro</i> observations were used for discussion of the effects of temperature on growth and activity of <i>C. fraxinea</i> <i>in vivo</i>.

scholarly journals In silico screening leads to novel scaffolds with both antifungal and anti-NLRP3 inflammasome activity

2021 ◽  
Vol 3 (12) ◽  
Author(s):  
David Lowes ◽  
Rand Al-waqfi ◽  
Kirk Hevener ◽  
Brian Peters
Keyword(s):  
Nlrp3 Inflammasome ◽  
In Silico ◽  
Fungal Growth ◽  
Hyphal Growth ◽  
Acetohydroxyacid Synthase ◽  
In Silico Screening ◽  
Chemical Structures ◽  
Ic50 Values

Due to structural similarities that exist between established inhibitors of the NLRP3-inflammasome, sulfonylureas Glyburide and MCC-950, and herbicidal-sulfonylureas, that specifically target fungal acetohydroxyacid synthase (AHAS), we sought to determine the potential for compounds to block both inflammation and inhibit fungal growth. In silico screening of ∼250,000 compounds was used to identify a prioritized list of chemical structures capable of inhibiting both targets. Prioritization of the top 1% of scores identified ∼70 compounds with a diverse set of scaffolds for testing in vitro. Selected hits were used to assess anti-inflammatory function in a THP-1 challenge model with LPS+ATP and resulting IC50 values were obtained. MIC and hyphal-growth assays were conducted to determine potential antifungal activity using media depleted of branched chain amino acids isoleucine and valine, to confirm on target AHAS inhibition. Identification of hits that exhibited low micromolar activity for NLRP3 and AHAS inhibition were selected for SAR study. In vitro testing of the analogs along with molecular docking led to increased knowledge for lead optimization of the potential hits. In silico screening has resulted in IC50 (IL-1β release) and MIC50 (fungal growth) values with low μM potency against several Candida species. In vivo validation will further confirm the potential of the scaffolds for further synthetic-modification for the rationale design of novel dual-purpose drugs

Tetrandrine, a potent antifungal agent: inhibits mycelial growth and virulence of Botrytis cinerea

2020 ◽  
Author(s):  
Pingliang Li ◽  
jian zou ◽  
Yanhan Dong ◽  
jintao Jiang ◽  
Wenxing Liang ◽  
...  
Keyword(s):  
Botrytis Cinerea ◽  
Antifungal Agent ◽  
Plant Pathogens ◽  
Efflux Pump ◽  
Hyphal Growth ◽  
Tomato Plants ◽  
Low Concentrations ◽  
Grey Mold

Tetrandrine (TET) is a potent calcium channel blocker used for the treatment of hypertension and inflammation. Currently, TET is predominantly used to treat a variety of human diseases, and there is little information regarding the use of TET against plant pathogens. In this study, we explored the antifungal activity of TET on a plant pathogen, Botrytis cinerea. We show that administration of low concentrations of TET effectively inhibited hyphal growth of fungus grown on potato dextrose agarose, and decreased the virulence of B. cinerea in tomato plants. Real-time PCR revealed that the expression of drug efflux pump related genes (alcohol dehydrogenase 1, multi-drug/pheromone exporter, pleiotropic drug resistance protein 1, and synaptic vesicle transporter) were down-regulated in the presence of TET. Finally, we show that TET acts synergistically with iprodione, resulting in increased inhibition of B. cinerea both in vitro and in vivo. These results indicate that TET might act as an effective antifungal agent in reducing grey mold disease.

In vitro and in vivo activity of chelerythrine against Candida albicans and underlying mechanisms

2019 ◽  
Vol 14 (18) ◽  
pp. 1545-1557 ◽  
Author(s):  
Ying Gong ◽  
Siwen Li ◽  
Weixin Wang ◽  
Yiman Li ◽  
Wenli Ma ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Antifungal Activity ◽  
Calcium Concentration ◽  
Galleria Mellonella ◽  
Hyphal Growth ◽  
Drug Transporter ◽  
Antifungal Effect ◽  
Underlying Mechanisms

Aim: To evaluate whether chelerythrine (CHT) exhibited antifungal activity against Candida albicans in vitro and in vivo and to explore the underlying mechanisms. Materials & methods: Broth microdilution assay and Galleria mellonella model were used to evaluate the antifungal effect in vitro and in vivo, respectively. Mechanism studies were investigated by morphogenesis observation, Fluo-3/AM, DCFH-DA and rhodamine6G assay, respectively. Results: CHT exhibited antifungal activity against C. albicans and preformed biofilms with minimum inhibitory concentrations ranged from 2 to 16 μg/ml. Besides, CHT protected G. mellonella larvae infected by C. albicans. Mechanisms studies revealed that CHT inhibited hyphal growth, increased intracellular calcium concentration, induced accumulation of reactive oxygen species and inhibited drug transporter activity. Conclusion: CHT exhibited antifungal activity against C. albicans.

Effects of Temperature on Metabolism of Benzo[a]pyrene by Toadfish (Opsanus beta) Hepatocytes

1990 ◽  
Vol 47 (4) ◽  
pp. 831-837 ◽  
Author(s):  
Kenneth A. Gill ◽  
Patrick J. Walsh
Keyword(s):  
Phase I ◽  
Phase Ii ◽  
In Vivo Studies ◽  
Kinetic Properties ◽  
Opsanus Beta ◽  
Effects Of Temperature ◽  
Lower Temperature ◽  
Phase Ii Metabolites

Prior in vivo studies of the effects of temperature on uptake, metabolism and excretion of benzo[a]pyrene (BaP) by the gulf toadfish (Opsanus beta) suggested that metabolism of BaP may be partially temperature insensitive under certain conditions. In the present study, hepatocytes were isolated from toadfish acclimated to 18 or 28 °C, and then cells were exposed to BaP at 18, 23, and 28 °C in vitro to more directly examine the effects of temperature on metabolism. Toadfish hepatocytes metabolized BaP to a variety of Phase I and Phase II metabolites in similar proportions to toadfish in vivo, with the exception that fewer Phase I metabolites were detected. A marked temperature dependence of metabolism of BaP to Phase II metabolites was noted between 18 and 28 °C at near saturating concentration of BaP (13 μg∙mL−1). Warm-acclimated toadfish displayed a lower temperature sensitivity than cold-acclimated toadfish (Q10, the ratio of the rate at T + 10 °C: rate at T = 1.85 and 2.65, respectively). However, at a lower, subsaturating concentration of BaP (5 μg∙mL−1), production of all metabolites showed a marked temperature independence. We speculate that this independence is the result of temperature effects on the kinetic properties of the enzymes of xenobiotic metabolism.

scholarly journals Candida albicans Septin Mutants Are Defective for Invasive Growth and Virulence

2003 ◽  
Vol 71 (7) ◽  
pp. 4045-4051 ◽  
Author(s):  
Amy J. Warenda ◽  
Sarah Kauffman ◽  
Taylor P. Sherrill ◽  
Jeffrey M. Becker ◽  
James B. Konopka
Keyword(s):  
Candida Albicans ◽  
Systemic Infection ◽  
Hyphal Growth ◽  
Invasive Growth ◽  
Important Virulence Factor ◽  
Opportunistic Human Pathogen ◽  
Cytoskeletal Elements ◽  
Organ Invasion

ABSTRACT Hyphal growth of Candida albicans is implicated as an important virulence factor for this opportunistic human pathogen. Septin proteins, a family of cytoskeletal elements that regulate membrane events and are important for proper morphogenesis of C. albicans, were examined for their role in tissue invasion and virulence in the mouse model of systemic infection. In vitro, septin mutants are only mildly defective for hyphal growth in liquid culture but display pronounced defects for invasive growth into agar. In vivo, the septin mutants were found to exhibit attenuated virulence. However, mice infected with the mutants displayed high fungal burdens in their kidneys without obvious symptoms of disease. Histological examination of infected kidneys revealed defects in organ invasion for the cdc10Δ and cdc11Δ deletion mutants, which displayed both reduced tissue penetration and noninvasive fungal masses. Thus, the septin proteins are necessary for invasive growth, which appears to be more important to the successful pathogenesis of C. albicans than hyphal growth alone.

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