scholarly journals Mechanistic basis for loss of water balance in green tree frogs infected with a fungal pathogen

2019 ◽  
Vol 317 (2) ◽  
pp. R301-R311 ◽  
Author(s):  
Nicholas C. Wu ◽  
Callum McKercher ◽  
Rebecca L. Cramp ◽  
Craig E. Franklin
Keyword(s):  
Water Balance ◽  
Water Uptake ◽  
Fungal Pathogen ◽  
Batrachochytrium Dendrobatidis ◽  
Osmotic Regulation ◽  
Water Fluxes ◽  
Uptake Rates ◽  
Osmotic Homeostasis ◽  
Ventral Skin

Chytridiomycosis, a lethal skin disease caused by the fungal pathogen Batrachochytrium dendrobatidis ( Bd), disrupts skin function of amphibians, interfering with ionic and osmotic regulation. To regulate fungal loads, amphibians increase their rate of skin sloughing. However, sloughing also causes a temporary loss of ionic and osmotic homeostasis due to disruption of the skin, a key osmoregulatory organ. The combined effects of increased sloughing frequency and chytridiomycosis contribute to the high rates of mortality from Bd infections. However, the mechanisms responsible for the loss of cutaneous osmotic regulation remain unknown. We measured the changes in whole animal water uptake rates, in vitro transcutaneous water fluxes across the ventral skin, and the mRNA expression of epithelial water transport proteins (aquaporins, AQPs) and junctional proteins in Bd-infected and uninfected Litoria caerulea skin. We hypothesize that infected frogs would show reduction/inhibition in cutaneous water transporters responsible for regulating water balance, and sloughing would exacerbate cutaneous water fluxes. We found that infected, nonsloughing frogs had an impaired rate of water uptake and showed increased rates of in vitro water efflux across the ventral skin. In uninfected frogs, the expression of AQPs and junction genes increased significantly with sloughing, which may assist in regulating cutaneous water movements and barrier function in the newly exposed skin. In contrast, infected frogs did not show this postsloughing increase in AQP gene expression. The combination of increased sloughing frequency, impaired water uptake rates, and increased rates of water loss likely contributes to the loss of osmotic homeostasis in frogs infected with Bd.

scholarly journals A Fungal Pathogen of Amphibians, Batrachochytrium dendrobatidis, Attenuates in Pathogenicity with In Vitro Passages

PLoS ONE ◽  
2013 ◽  
Vol 8 (10) ◽  
pp. e77630 ◽  
Author(s):  
Penny F. Langhammer ◽  
Karen R. Lips ◽  
Patricia A. Burrowes ◽  
Tate Tunstall ◽  
Crystal M. Palmer ◽  
...  
Keyword(s):  
Fungal Pathogen ◽  
Batrachochytrium Dendrobatidis

scholarly journals Photocuring Hyaluronic Acid/Silk Fibroin Hydrogel Containing Curcumin Loaded CHITOSAN Nanoparticles for the Treatment of MG-63 Cells and ME3T3-E1 Cells

Polymers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 2302
Author(s):  
Qingwen Yu ◽  
Zhiyuan Meng ◽  
Yichao Liu ◽  
Zehao Li ◽  
Xing Sun ◽  
...  
Keyword(s):  
Hyaluronic Acid ◽  
Bone Regeneration ◽  
Water Uptake ◽  
Silk Fibroin ◽  
Bone Repair ◽  
Ph Value ◽  
Chitosan Nanoparticles ◽  
Vitro Assay ◽  
Long Term Treatment

After an osteosarcoma excision, recurrence and bone defects are significant challenges for clinicians. In this study, the curcumin (Cur) loaded chitosan (CS) nanoparticles (CCNP) encapsulated silk fibroin (SF)/hyaluronic acid esterified by methacrylate (HAMA) (CCNPs-SF/HAMA) hydrogel for the osteosarcoma therapy and bone regeneration was developed by photocuring and ethanol treatment. The micro or nanofibers networks were observed in the CCNPs-SF/HAMA hydrogel. The FTIR results demonstrated that alcohol vapor treatment caused an increase in β-sheets of SF, resulting in the high compression stress and Young’s modulus of CCNPs-SF/HAMA hydrogel. According to the water uptake analysis, SF caused a slight decrease in water uptake of CCNPs-SF/HAMA hydrogel while CCNPs could enhance the water uptake of it. The swelling kinetic results showed that both the CCNPs and the SF increased the swelling ratio of CCNPs-SF/HAMA hydrogel. The accumulative release profile of CCNPs-SF/HAMA hydrogel showed that the release of Cur from CCNPs-SF/HAMA hydrogel was accelerated when pH value was decreased from 7.4 to 5.5. Besides, compared with CCNPs, the CCNPs-SF/HAMA hydrogel had a more sustainable drug release, which was beneficial for the long-term treatment of osteosarcoma. In vitro assay results indicated that CCNPs-SF/HAMA hydrogel with equivalent Cur concentration of 150 μg/mL possessed both the effect of anti-cancer and promoting the proliferation of osteoblasts. These results suggest that CCNPs-SF/HAMA hydrogel with superior physical properties and the bifunctional osteosarcoma therapy and bone repair may be an excellent candidate for local cancer therapy and bone regeneration.

scholarly journals Trojan Horse Transit Contributes to Blood-Brain Barrier Crossing of a Eukaryotic Pathogen

mBio ◽  
2017 ◽  
Vol 8 (1) ◽  
Author(s):  
Felipe H. Santiago-Tirado ◽  
Michael D. Onken ◽  
John A. Cooper ◽  
Robyn S. Klein ◽  
Tamara L. Doering
Keyword(s):  
Experimental Evidence ◽  
Cryptococcus Neoformans ◽  
Blood Brain Barrier ◽  
Fungal Pathogen ◽  
Trojan Horse ◽  
Brain Barrier ◽  
Barrier Crossing ◽  
Blood Brain ◽  
The Brain

ABSTRACT The blood-brain barrier (BBB) protects the central nervous system (CNS) by restricting the passage of molecules and microorganisms. Despite this barrier, however, the fungal pathogen Cryptococcus neoformans invades the brain, causing a meningoencephalitis that is estimated to kill over 600,000 people annually. Cryptococcal infection begins in the lung, and experimental evidence suggests that host phagocytes play a role in subsequent dissemination, although this role remains ill defined. Additionally, the disparate experimental approaches that have been used to probe various potential routes of BBB transit make it impossible to assess their relative contributions, confounding any integrated understanding of cryptococcal brain entry. Here we used an in vitro model BBB to show that a “Trojan horse” mechanism contributes significantly to fungal barrier crossing and that host factors regulate this process independently of free fungal transit. We also, for the first time, directly imaged C. neoformans-containing phagocytes crossing the BBB, showing that they do so via transendothelial pores. Finally, we found that Trojan horse crossing enables CNS entry of fungal mutants that cannot otherwise traverse the BBB, and we demonstrate additional intercellular interactions that may contribute to brain entry. Our work elucidates the mechanism of cryptococcal brain invasion and offers approaches to study other neuropathogens. IMPORTANCE The fungal pathogen Cryptococcus neoformans invades the brain, causing a meningoencephalitis that kills hundreds of thousands of people each year. One route that has been proposed for this brain entry is a Trojan horse mechanism, whereby the fungus crosses the blood-brain barrier (BBB) as a passenger inside host phagocytes. Although indirect experimental evidence supports this intriguing mechanism, it has never been directly visualized. Here we directly image Trojan horse transit and show that it is regulated independently of free fungal entry, contributes to cryptococcal BBB crossing, and allows mutant fungi that cannot enter alone to invade the brain. IMPORTANCE The fungal pathogen Cryptococcus neoformans invades the brain, causing a meningoencephalitis that kills hundreds of thousands of people each year. One route that has been proposed for this brain entry is a Trojan horse mechanism, whereby the fungus crosses the blood-brain barrier (BBB) as a passenger inside host phagocytes. Although indirect experimental evidence supports this intriguing mechanism, it has never been directly visualized. Here we directly image Trojan horse transit and show that it is regulated independently of free fungal entry, contributes to cryptococcal BBB crossing, and allows mutant fungi that cannot enter alone to invade the brain.

In vitro selection of a fungal pathogen for use against Diaphorina citri

2015 ◽  
Vol 90 ◽  
pp. 6-15 ◽  
Author(s):  
N. Orduño-Cruz ◽  
A.W. Guzmán-Franco ◽  
E. Rodríguez-Leyva ◽  
R. Alatorre-Rosas ◽  
H. González-Hernández ◽  
...  
Keyword(s):  
Fungal Pathogen ◽  
In Vitro Selection ◽  
Diaphorina Citri ◽  
Selection Of

scholarly journals Application of Double-Strand RNAs Targeting Chitin Synthase, Glucan Synthase, and Protein Kinase Reduces Fusarium graminearum Spreading in Wheat

2021 ◽  
Vol 12 ◽  
Author(s):  
Peng Yang ◽  
Shu-Yuan Yi ◽  
Jun-Na Nian ◽  
Qing-Song Yuan ◽  
Wei-Jie He ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Fusarium Graminearum ◽  
Fungal Pathogen ◽  
Chitin Synthase ◽  
Mycelium Growth ◽  
Rnai Construct ◽  
Glucan Synthase ◽  
Kinase C ◽  
Wheat Leaves

Controlling the devastating fungal pathogen Fusarium graminearum (Fg) is a challenge due to inadequate resistance in nature. Here, we report on the identification of RNAi molecules and their applications for controlling Fg in wheat through silencing chitin synthase 7 (Chs7), glucan synthase (Gls) and protein kinase C (Pkc). From transgenic Fg strains four RNAi constructs from Chs7 (Chs7RNAi−1, −2, −3, and −4), three RNAi constructs from Gls (GlsRNAi−2, −3, and −6), and one RNAi construct from Pkc (PkcRNAi−5) were identified that displayed effective silencing effects on mycelium growth in medium and pathogenicity in wheat spikes. Transcript levels of Chs7, Gls and Pkc were markedly reduced in those strains. Double-strand RNAs (dsRNAs) of three selected RNAi constructs (Chs7RNAi-4, GlsRNAi-6 and PkcRNA-5) strongly inhibited mycelium growth in vitro. Spray of those dsRNAs on detached wheat leaves significantly reduced lesion sizes; the independent dsRNAs showed comparable effects on lesions with combination of two or three dsRNAs. Expression of three targets Chs7, Gls, and Pkc was substantially down-regulated in Fg-infected wheat leaves. Further application of dsRNAs on wheat spikes in greenhouse significantly reduced infected spikelets. The identified RNAi constructs may be directly used for spray-induced gene silencing and stable expression in plants to control Fusarium pathogens in agriculture.

scholarly journals Sour cherry anthracnose and possibilities of the control with special regard to resident Glomerella population in sour cherry plantations of East Hungary

2010 ◽  
pp. 12-17 ◽  
Author(s):  
Gyula Oros ◽  
László Vajna ◽  
Klára Balázs ◽  
Zoltán Fekete ◽  
Zoltán Naár ◽  
...  
Keyword(s):  
Fruit Ripening ◽  
Fungal Pathogen ◽  
Colletotrichum Gloeosporioides ◽  
Rapid Development ◽  
Sour Cherry ◽  
Control Measures ◽  
Yield Losses ◽  
Trichoderma Species ◽  
Special Regard

Anthracnose is considered one of the most destructive diseases for sour cherry production due to the rapid development of the disease on fruits. Glomerella cingulata (Stoneman) Spauld. & H. Schrenk (anam.: Colletotrichum gloeosporioides (Penz.) Penz. & Sacc. in Penz.) has been the fungal pathogen responsible for anthracnose in last decades. Yield losses greater than 90% may occur under epidemic conditions. C. acutatum (J.H. Simmonds, 1968) strains were isolated of sourcherry plantations in East Hungary and this pathogen, new for Hungarian microbiont became recently dominant. Contrarily to the former species it is certainly transmitted with ants during fruit ripening. About third of strains proved to be cutinase producers that enable them to actively penetrate via cuticule, and these strains infect directly berries of blackberry, grape and tomato as well as plum and apple. Most of cutinase negative strains could also infect these fruits after mechanic injury. All strains of both species produce amylase, cellulase, lecithinase, lipase, polyfenoloxydase and protease in vitro, although the activity of these enzymes highly varied in the medium. The only C. acutatum strains produced noticeable amount of chitinase. Strains, tolerant to recently applied fungicides to control the anthracnose, could be isolated of sour cherry plantations that might be the cause of ineffectiveness of control measures in 2010. The mycofungicide containing mixture of three Trichoderma species in oil carrier could efficiently depress the development of anthracnose in ripening sour cherry.

scholarly journals Suppression of Stem-End Rot on Avocado Fruit Using Trichoderma spp. in the Central Highlands of Kenya

2021 ◽  
Vol 2021 ◽  
pp. 1-6
Author(s):  
E. K. Wanjiku ◽  
J. W. Waceke ◽  
J. N. Mbaka
Keyword(s):  
Growth Inhibition ◽  
Fungal Pathogen ◽  
Mycelial Growth ◽  
Culture Technique ◽  
Global Market ◽  
Dual Culture ◽  
Postharvest Diseases ◽  
Trichoderma Spp ◽  
Lasiodiplodia Theobromae

Demand for organic avocado fruits, together with stringent food safety standards in the global market, has made producers to use alternative, safe, and consumer-friendly strategies of controlling the postharvest fungal disease of avocado fruits. This study assessed the in vitro efficacy of Trichoderma spp. (T. atroviride, T. virens, T. asperellum, and T. harzianum) against isolated avocado stem-end rot (SER) fungal pathogens (Lasiodiplodia theobromae, Neofusicoccum parvum, Nectria pseudotrichia, and Fusarium solani) using a dual culture technique. The Trichoderma spp. were also evaluated singly on postharvest “Hass” avocado fruits. Spore suspension at 5 × 104 conidial/ml of the Trichoderma spp. was applied on the avocado fruits at three time points, twenty-four hours before the fungal pathogen (preinoculation), at the same time as the fungal pathogen (concurrent inoculation), and 24 hours after the fungal pathogen (postinoculation). In the in vitro study, T. atroviride showed the highest mycelial growth inhibition against N. parvum (48%), N. pseudotrichia (55%), and F. solani (32.95%), while T. harzianum had the highest mycelial growth inhibition against L. theobromae. Trichoderma asperellum was the least effective in inhibiting the mycelial growth of all the pathogens. Similarly, T. virens showed the highest mycelial growth inhibition against N. pseudotrichia at 45% inhibition. On postharvest “Hass” fruits, T. atroviride showed the highest efficacy against N. parvum, N. pseudotrichia, and F. solani in all the applications. Trichoderma virens and T. harzianum were most effective against all the pathogens during postinoculation, while Lasiodiplodia theobromae was best controlled by T. virens, T. harzianum, and T. asperellum during postinoculation. Both T. atroviride and T. harzianum present a potential alternative to synthetic fungicides against postharvest diseases of avocado fruits, and further tests under field conditions to be done to validate their efficacy. The possibility of using Trichoderma spp. in the management of SER on avocado fruits at a commercial level should also be explored.

scholarly journals ISOLATION OF ANTIFUNGI BACTERIA FROM BANANA RHIZOSPHERE TO INHIBIT Fusarium Oxysproum f.sp cubense (FOC) GROWTH

2019 ◽  
Vol 5 (3) ◽  
pp. 105
Author(s):  
Albert Sembiring ◽  
Natalia Lusianingsih Sumanto
Keyword(s):  
Fungal Pathogen ◽  
Room Temperature ◽  
Biocontrol Agent ◽  
Vascular Tissue ◽  
Agar Medium ◽  
Wilt Disease ◽  
In Vitro Test ◽  
Panama Disease ◽  
Vitro Test

Fusarium wilt disease on banana has been known as panama disease one of the main diseases that cause huge losses for banana farmers. It is caused by the soil-borne fungal pathogen, Fusarium oxysporum f.sp cubense (Foc), which is very hard control because it is saprophytic in the soil. The mold infiltrates the root to vascular tissue that induces yellowing on the leaf, so this pathogen can attack the root, stem dan leaf. The research aimed to search bacteria from the banana rhizosphere that have an antifungal activity to inhibit Foc growth. Bacteria was isolated by serial dilution then was spread on King’s B agar medium incubation 28oC (room temperature). Four quadrants in vitro test on PDA medium used twenty bacterial from isolation, from the test was obtained six isolates have the potential to inhibit the growth of Foc. Based on percentage inhibition radial growth four isolates that have inhibition 50% over which TR2 was the highest at 79.07%. The in vitro test confirmed that bacteria from the banana rhizosphere have potential as biocontrol agent because it was able to inhibit the Foc growth.

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