scholarly journals DNM1, a Dynamin-Related Protein That Contributes to Endocytosis and Peroxisome Fission, Is Required for the Vegetative Growth, Sporulation, and Virulence of Metarhizium robertsii

2020 ◽  
Vol 86 (17) ◽  
Author(s):  
Xiangyun Xie ◽  
Yulong Wang ◽  
Deshui Yu ◽  
Rui Xie ◽  
Zhenbang Liu ◽  
...  
Keyword(s):  
Entomopathogenic Fungi ◽  
Vegetative Growth ◽  
Cell Function ◽  
Galleria Mellonella ◽  
Morphological Changes ◽  
Metarhizium Robertsii ◽  
Content Type ◽  
Cellular Processes ◽  
Transport Vesicles ◽  
Related Proteins

ABSTRACT Although dynamins and dynamin-related proteins (DRPs), a large GTPase superfamily, are involved in the budding of transport vesicles and division of organelles in eukaryotic cells, the function of these proteins in entomopathogenic fungi has not been reported to date. Here, DNM1, a DRP in Metarhizium robertsii, was characterized using gene disruption and complementation strategies. Mutant phenotype assays showed that the ΔDnm1 strain displayed increased defects in radial growth (∼24%) and conidial production (∼42%) compared to those of the wild type (WT), and reduced conidiation levels were accompanied by the repression of several key conidiation-related genes, including flbA, wetA, and flbD. Additionally, mutant bioassays revealed that disruption of Dnm1 impaired the virulence (both topical inoculation and injection) of M. robertsii in the insect Galleria mellonella. Further analysis demonstrated that deleting Dnm1 in fungi suppressed the transcriptional levels of several virulence genes in the insect hemocoel. Moreover, we found that DNM1 colocalized with peroxisomes and mitochondria. Importantly, disruption of Dnm1 abolished normal fungal endocytosis, resulting in significantly decreased numbers of, as well as morphological changes in, peroxisomes. These findings indicate that deletion of Dnm1 causes significant changes in the vegetative growth, sporulation, and virulence of M. robertsii due to changes in cell function and peroxisomes. IMPORTANCE Dnm1 was found to be involved in fungal development and virulence, mediated peroxisomal fission, and normal endocytosis. This finding provides new insights into the cellular processes and pathogenicity in entomopathogenic fungi.

scholarly journals Expression of a Toll Signaling Regulator Serpin in a Mycoinsecticide for Increased Virulence

2014 ◽  
Vol 80 (15) ◽  
pp. 4531-4539 ◽  
Author(s):  
Linzhi Yang ◽  
Nemat O. Keyhani ◽  
Guirong Tang ◽  
Chuang Tian ◽  
Ruipeng Lu ◽  
...  
Keyword(s):  
Entomopathogenic Fungi ◽  
Galleria Mellonella ◽  
Lethal Dose ◽  
Defense Responses ◽  
Content Type ◽  
Greater Wax Moth ◽  
Wide Range ◽  
New Strategy

ABSTRACTSerpins are ubiquitously distributed serine protease inhibitors that covalently bind to target proteases to exert their activities. Serpins regulate a wide range of activities, particularly those in which protease-mediated cascades are active. TheDrosophila melanogasterserpin Spn43Ac negatively controls the Toll pathway that is activated in response to fungal infection. The entomopathogenic fungusBeauveria bassianaoffers an environmentally friendly alternative to chemical pesticides for insect control. However, the use of mycoinsecticides remains limited in part due to issues of efficacy (low virulence) and the recalcitrance of the targets (due to strong immune responses). Since Spn43Ac acts to inhibit Toll-mediated activation of defense responses, we explored the feasibility of a new strategy to engineer entomopathogenic fungi with increased virulence by expression of Spn43Ac in the fungus. Compared to the 50% lethal dose (LD50) for the wild-type parent, the LD50ofB. bassianaexpressing Spn43Ac (strain Bb::S43Ac-1) was reduced ∼3-fold, and the median lethal time against the greater wax moth (Galleria mellonella) was decreased by ∼24%, with the more rapid proliferation of hyphal bodies being seen in the host hemolymph.In vitroandin vivoassays showed inhibition of phenoloxidase (PO) activation in the presence of Spn43Ac, with Spn43Ac-mediated suppression of activation by chymotrypsin, trypsin, laminarin, and lipopolysaccharide occurring in the following order: chymotrypsin and trypsin > laminarin > lipopolysaccharide. Expression of Spn43Ac had no effect on the activity of the endogenousB. bassiana-derived cuticle-degrading protease (CDEP-1). These results expand our understanding of Spn43Ac function and confirm that suppression of insect immune system defenses represents a feasible approach to engineering entomopathogenic fungi for greater efficacy.

scholarly journals A response of entomopathogenic fungi to botanical fungicides and synthetic fungicides in vitro

2012 ◽  
Vol 58 (1) ◽  
pp. 101-111
Author(s):  
Anna Sapieha-Waszkiewicz ◽  
Barbara Marjańska-Cichoń ◽  
Ryszard Miętkiewski ◽  
Mieczysław Żurek
Keyword(s):  
Beauveria Bassiana ◽  
Entomopathogenic Fungi ◽  
Metarhizium Anisopliae ◽  
Galleria Mellonella ◽  
Morphological Changes ◽  
Fungal Growth ◽  
Apple Orchard ◽  
Paecilomyces Fumosoroseus ◽  
Arable Field

The growth colonies' morphology and sporulation of entomopathogenic fungi was estimated on Sabouraud medium containing botanical fungicides (Bioczos liquid and Biosept 33 SL), and synthetic ones (Teldor 500 SC and Sumilex 500 SC). Entomopathogenic fungi (<i>Beauveria bassiana</i> (Balls.) Vuill., <i>Metarhizium anisopliae</i> (Metsch.) Sorok, and <i>Paecilomyces fumosoroseus</i> (Wize) Brown et Smith.), were isolated from soil by means of <i>Galleria mellonella</i> larvae as baits. Isolates Bb I, Ma I, Pf I derivered from herbicide fallow from apple orchard and isolates Bb II, Ma II and Pf II from arable field adjacent to orchard. Fungicides were added to Sabouraud medium at the following concentrations: A-recommended dose, B-10-times lower than the recommended, C-100-times lower than the recommended. The growth of colonies their morphological changes and sporulations were estimated after 5 and 20 days. The same parametrs were observed when fungi were transfered from the medium containing fungicides on the medium with out fungicides. From botanical fungicides Bioczos liquid inhibited fungal growth more than Biosept 33 SL. Both of fungicides were most toxic to fungi at concentration A. Both of <i>P. fumosoroseus</i> isolates were the most sensitive to Bioczos liquid and <i>M. anisopliae</i> to Biosept 33 SL. All concentrations of synthetic fungicides (Sumilex 500 SC, Teldor 500 SC) restricted growth of <i>B. bassiana</i> and <i>M. anisopliae</i> isolates more from arable soil than from herbicide fallow but opposite reaction was found with respect to <i>P. fumosoroseus</i>.

scholarly journals Paradoxical Growth of Candida albicans in the Presence of Caspofungin Is Associated with Multiple Cell Wall Rearrangements and Decreased Virulence

2013 ◽  
Vol 58 (2) ◽  
pp. 1071-1083 ◽  
Author(s):  
Cristina Rueda ◽  
Manuel Cuenca-Estrella ◽  
Oscar Zaragoza
Keyword(s):  
Cell Wall ◽  
Candida Albicans ◽  
Galleria Mellonella ◽  
Morphological Changes ◽  
Antifungal Drugs ◽  
Proinflammatory Response ◽  
Content Type ◽  
Multiple Cell ◽  
Fungal Adaptation ◽  
Paradoxical Growth

ABSTRACTIn the last decade, echinocandins have emerged as an important family of antifungal drugs because of their fungicidal activity againstCandidaspp. Echinocandins inhibit the enzyme β-1,3-d-glucan synthase, encoded by theFKSgenes, and resistance to echinocandins is associated with mutations in this gene. In addition, echinocandin exposure can produce paradoxical growth, defined as the ability to grow at high antifungal concentrations but not at intermediate concentrations. In this work, we have demonstrated that paradoxical growth ofCandida albicansin the presence of caspofungin is not due to antifungal degradation or instability. Media with high caspofungin concentrations recovered from wells whereC. albicansshowed paradoxical growth inhibited the growth of aCandida kruseireference strain. Cells exhibiting paradoxical growth at high caspofungin concentrations showed morphological changes such as enlarged size, abnormal septa, and absence of filamentation. Chitin content increased from the MIC to high caspofungin concentrations. Despite the high chitin levels, around 23% of cells died after treatment with caspofungin, indicating that chitin is required but not sufficient to protect the cells from the fungicidal effect of caspofungin. Moreover, we found that after paradoxical growth, β-1,3-glucan was exposed at the cell wall surface. Cells grown at high caspofungin concentrations had decreased virulence in the invertebrate hostGalleria mellonella. Cells grown at high caspofungin concentrations also induced a proinflammatory response in murine macrophages compared to control cells. Our work highlights important aspects about fungal adaptation to caspofungin, and although this adaptation is associated with reduced virulence, the clinical implications remain to be elucidated.

scholarly journals Effect of Soil Chemical Properties on the Occurrence and Distribution of Entomopathogenic Fungi in Portuguese Grapevine Fields

Pathogens ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 137
Author(s):  
Lav Sharma ◽  
Irene Oliveira ◽  
Fátima Gonçalves ◽  
Fernando Raimundo ◽  
Rupesh Kumar Singh ◽  
...  
Keyword(s):  
Beauveria Bassiana ◽  
Entomopathogenic Fungi ◽  
Galleria Mellonella ◽  
Organic Matter Content ◽  
Chemical Properties ◽  
Principal Component ◽  
Clonostachys Rosea ◽  
Total N ◽  
Metarhizium Robertsii ◽  
Exchangeable K

Entomopathogenic fungi (EPF) contribute to different ecosystem services. However, factors affecting their natural occurrences in soil remain poorly understood. In a previous study, 81 soil samples were subjected to insect baiting using Galleria mellonella and Tenebrio molitor to isolate EPF from Portuguese vine farms. Here, soils yielding any of the four common EPF, i.e., Beauveria bassiana, Purpureocillium lilacinum, Metarhizium robertsii, and Clonostachys rosea f. rosea, were correlated with their chemical properties. Beauveria bassiana was negatively affected by higher available P (p = 0.02), exchangeable K-ions (p = 0.016) and positively affected by higher soil pH_H2O (p = 0.021). High exchangeable K-ions inhibited P. lilacinum (p = 0.011) and promoted C. rosea f. rosea (p = 0.03). Moreover, high available K also suppressed P. lilacinum (p = 0.027). Metarhizium robertsii was inhibited by higher organic matter content (p = 0.009), higher C:N (p = 0.017), total N (p = 0.007), and exchangeable Mg-ions (p = 0.026), and promoted by higher exchangeable Na-ions (p = 0.003). Nonetheless, mean comparisons and principal component analysis suggested that higher soil pH and exchangeable Ca-ions have contrasting effects on EPF occurrences, as they promote B. bassiana and inhibit M. robertsii. Herbicides did not seem to affect EPF presence. Overall, this study is among the first reports on the effects of soil chemistry on EPF other than Metarhizium, and will facilitate biological pest management approaches.

scholarly journals PakD, a Putative p21-Activated Protein Kinase in Dictyostelium discoideum, Regulates Actin

2013 ◽  
Vol 13 (1) ◽  
pp. 119-126 ◽  
Author(s):  
Miguel Garcia ◽  
Sibnath Ray ◽  
Isaiah Brown ◽  
Jon Irom ◽  
Derrick Brazill
Keyword(s):  
Protein Kinase ◽  
Actin Cytoskeleton ◽  
Dictyostelium Discoideum ◽  
Cell Function ◽  
Actin Dynamics ◽  
Wild Type ◽  
Content Type ◽  
Multicellular Development ◽  
Actin Organization ◽  
Cellular Processes

ABSTRACT Proper regulation of the actin cytoskeleton is essential for cell function and ultimately for survival. Tight control of actin dynamics is required for many cellular processes, including differentiation, proliferation, adhesion, chemotaxis, endocytosis, exocytosis, and multicellular development. Here we describe a putative p21-activated protein kinase, PakD, that regulates the actin cytoskeleton in Dictyostelium discoideum . We found that cells lacking pakD are unable to aggregate and thus unable to develop. Compared to the wild type, cells lacking PakD have decreased membrane extensions, suggesting defective regulation of the actin cytoskeleton. pakD − cells show poor chemotaxis toward cyclic AMP (cAMP) but normal chemotaxis toward folate, suggesting that PakD mediates some but not all chemotaxis responses. pakD − cells have decreased polarity when placed in a cAMP gradient, indicating that the chemotactic defects of the pakD − cells may be due to an impaired cytoskeletal response to cAMP. In addition, while wild-type cells polymerize actin in response to global stimulation by cAMP, pakD − cells exhibit F-actin depolymerization under the same conditions. Taken together, the results suggest that PakD is part of a pathway coordinating F-actin organization during development.

Modulation effects of hexamethylene bisacetamide on growth and differentiation of cultured human malignant glioma cells

1996 ◽  
Vol 84 (5) ◽  
pp. 831-838 ◽  
Author(s):  
Xiao-Nan Li ◽  
Zi-Wei Du ◽  
Qiang Huang
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
Malignant Glioma ◽  
Culture Media ◽  
Morphological Changes ◽  
Control Group ◽  
Cell Cycle Distribution ◽  
Content Type ◽  
Hexamethylene Bisacetamide ◽  
Human Malignant Glioma

✓ The modulation effects of hexamethylene bisacetamide (HMBA), a differentiation-inducing agent, on growth and differentiation of cells from human malignant glioma cell line SHG-44 were studied. At cytostatic doses (2.5 mM, 5 mM, 7.5 mM, and 10 mM for 15 days), HMBA exerted a marked inhibitory effect on cell proliferation. Exposure to HMBA (5 mM and 10 mM for 12 days) also resulted in an accumulation of cells in G0/G1 phase and a decrease of cells in S phase as analyzed by flow cytometry. The reversible effects of 7.5 mM HMBA and 10 mM HMBA on cell proliferation and 10 mM HMBA on disruption of cell cycle distribution were observed when HMBA was removed from culture media on Day 6 and replaced with HMBA-free media. Colony-forming efficiency (CFE) in soft agar was remarkably decreased by HMBA (2.5 mM, 5 mM, 7.5 mM, and 10 mM for 14 days), and in 7.5 mM HMBA— and 10 mM HMBA—treated cells, the CFEs were reduced to 25% and 12.5%, respectively, of that in untreated cells. Cells treated with HMBA (5 mM and 10 mM for 15 days) remained tumorigenic in athymic nude mice, but the growth rates of the xenografts were much slower than those in the control group. The effects of HMBA on cell proliferation, cell cycle distribution, CFE, and growth of xenografts were dose dependent. A more mature phenotype was confirmed by the morphological changes from spindle shape to large polygonal stellate shape and remarkably elevated expression of glial fibrillary acidic protein in cells exposed to HMBA (5 mM, 10 mM for 15 days). Our results showed that a more differentiated phenotype with marked growth arrest was induced in SHG-44 cells by HMBA.

scholarly journals Mechanical Sensing Element PDLIM5 Promotes Osteogenesis of Human Fibroblasts by Affecting the Activity of Microfilaments

Biomolecules ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 759
Author(s):  
Xiaolan Huang ◽  
Rongmei Qu ◽  
Yan Peng ◽  
Yuchao Yang ◽  
Tingyu Fan ◽  
...  
Keyword(s):  
Osteogenic Differentiation ◽  
Morphological Changes ◽  
Human Fibroblasts ◽  
Inhibitory Effect ◽  
Induction Medium ◽  
Sensing Element ◽  
Differentiation Potential ◽  
Osteogenic Induction Medium ◽  
Osteogenic Induction ◽  
Related Proteins

Human skin fibroblasts (HSFs) approximate the multidirectional differentiation potential of mesenchymal stem cells, so they are often used in differentiation, cell cultures, and injury repair. They are an important seed source in the field of bone tissue engineering. However, there are a few studies describing the mechanism of osteogenic differentiation of HSFs. Here, osteogenic induction medium was used to induce fibroblasts to differentiate into osteoblasts, and the role of the mechanical sensitive element PDLIM5 in microfilament-mediated osteogenic differentiation of human fibroblasts was evaluated. The depolymerization of microfilaments inhibited the expression of osteogenesis-related proteins and alkaline phosphatase activity of HSFs, while the polymerization of microfilaments enhanced the osteogenic differentiation of HSFs. The evaluation of potential protein molecules affecting changes in microfilaments showed that during the osteogenic differentiation of HSFs, the expression of PDLIM5 increased with increasing induction time, and decreased under the state of microfilament depolymerization. Lentivirus-mediated PDLIM5 knockdown by shRNA weakened the osteogenic differentiation ability of HSFs and inhibited the expression and morphological changes of microfilament protein. The inhibitory effect of knocking down PDLIM5 on HSF osteogenic differentiation was reversed by a microfilament stabilizer. Taken together, these data suggest that PDLIM5 can mediate the osteogenic differentiation of fibroblasts by affecting the formation and polymerization of microfilaments.

scholarly journals Biological Impact of a Large-Scale Genomic Inversion That Grossly Disrupts the Relative Positions of the Origin and Terminus Loci of theStreptococcus pyogenesChromosome

2019 ◽  
Vol 201 (17) ◽  
Author(s):  
Dragutin J. Savic ◽  
Scott V. Nguyen ◽  
Kimberly McCullor ◽  
W. Michael McShan
Keyword(s):  
Dna Sequences ◽  
Parental Strain ◽  
Large Scale ◽  
Galleria Mellonella ◽  
Acute Infection ◽  
Relative Length ◽  
Published Data ◽  
Rich Medium ◽  
Content Type

ABSTRACTA large-scale genomic inversion encompassing 0.79 Mb of the 1.816-Mb-longStreptococcus pyogenesserotype M49 strain NZ131 chromosome spontaneously occurs in a minor subpopulation of cells, and in this report genetic selection was used to obtain a stable lineage with this chromosomal rearrangement. This inversion, which drastically displaces theorisite relative to the terminus, changes the relative length of the replication arms so that one replichore is approximately 0.41 Mb while the other is about 1.40 Mb in length. Genomic reversion to the original chromosome constellation is not observed in PCR-monitored analyses after 180 generations of growth in rich medium. Compared to the parental strain, the inversion surprisingly demonstrates a nearly identical growth pattern in the first phase of the exponential phase, but differences do occur when resources in the medium become limited. When cultured separately in rich medium during prolonged stationary phase or in an experimental acute infection animal model (Galleria mellonella), the parental strain and the invertant have equivalent survival rates. However, when they are coincubated together, bothin vitroandin vivo, the survival of the invertant declines relative to the level for the parental strain. The accompanying aspect of the study suggests that inversions taking place nearoriCalways happen to secure the linkage oforiCto DNA sequences responsible for chromosome partition. The biological relevance of large-scale inversions is also discussed.IMPORTANCEBased on our previous work, we created to our knowledge the largest asymmetric inversion, covering 43.5% of theS. pyogenesgenome. In spite of a drastic replacement of origin of replication and the unbalanced size of replichores (1.4 Mb versus 0.41 Mb), the invertant, when not challenged with its progenitor, showed impressive vitality for growthin vitroand in pathogenesis assays. The mutant supports the existing idea that slightly deleterious mutations can provide the setting for secondary adaptive changes. Furthermore, comparative analysis of the mutant with previously published data strongly indicates that even large genomic rearrangements survive provided that the integrity of theoriCand the chromosome partition cluster is preserved.

Prevention of cerebral vasospasm after SAH with a thromboxane synthetase inhibitor, OKY-1581

1982 ◽  
Vol 57 (1) ◽  
pp. 74-82 ◽  
Author(s):  
Tomio Sasaki ◽  
Susumu Wakai ◽  
Takao Asano ◽  
Kintomo Takakura ◽  
Keiji Sano
Keyword(s):  
Cerebral Vasospasm ◽  
Morphological Changes ◽  
Content Type ◽  
Synthetase Inhibitor ◽  
Thromboxane Synthetase Inhibitor ◽  
Thromboxane Synthetase ◽  
Basilar Arteries ◽  
Blood Injection ◽  
Subarachnoid Blood ◽  
Fine Print

✓ The efficacy of thromboxane synthetase inhibitor in the prevention of cerebral vasospasm after subarachnoid hemorrhage (SAH) was evaluated in a prolonged experiment using dogs. Changes in the diameter of the basilar artery were followed by angiography, and morphological changes were studied by photomicroscopy and electron microscopy. As a thromboxane synthetase inhibitor, OKY-1581 (sodium-(E)-3-(4(-3-pyridylmethyl)phenyl)-2-methylacrylate)was used. Dogs received intravenous injections of 160 mg of OKY-1581 dissolved in 2 ml of physiological saline immediately after subarachnoid blood injection. Subsequently, the animals received continuous intravenous infusion of the drug at the rate of 4 gm/50 ml/24 hours until sacrifice 4 days after induction of SAH. Control dogs received subarachnoid blood injection without treatment with OKY-1581. Angiographic examination revealed that the late spasm was almost completely abolished by the treatment with OKY-1581. Early spasm was also prevented, but the drug's effect was less prominent than it was on the late spasm. Morphological study revealed degenerative changes in the endothelium and myonecrotic changes in the tunica media following SAH in the basilar arteries of the treated as well as the untreated dogs. However, corrugation of the internal elastic lamina was almost completely absent in the treated dogs. The above results indicate that a disproportionate synthesis of thromboxane A2 plays an important role in the evolution of chronic cerebral vasospasm following SAH, and that drugs such as OKY-1581 that selectively inhibit thromboxane synthetase might be useful in the prevention of vasospasm.

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