Modelling fungal growth with fractional transport models

Author(s):  
Huan Du ◽  
Patrick Perré ◽  
Ian Turner
Author(s):  
Kaibang Wu ◽  
Lai Wei ◽  
Zhengxiong Wang

Abstract The anomalous transport in magnetically confined plasmas is investigated by the radial fractional transport equations. It is shown that for fractional transport models, hollow density profiles are formed and uphill transports can be observed regardless of whether the fractional diffusion coefficients (FDCs) are radially dependent or not. When a radially dependent FDC Dα(r)<1 is imposed, compared with the case under Dα(r)=1.0, it is observed that the position of the peak of the density profile is closer to the core. Besides, it is found that when FDCs at the positions of source injections increase, the peak values of density profiles decrease. The non-local effect becomes significant as the order of fractional derivative α→1 and causes the uphill transport. However, as α→2, the fractional diffusion model returns to the standard model governed by Fick’s law.


Author(s):  
H.M. Mazzone ◽  
G. Wray ◽  
R. Zerillo

The fungal pathogen of the Dutch elm disease (DED), Ceratocystis ulmi (Buisman) C. Moreau, has eluded effective control since its introduction in the United States more than sixty years ago. Our studies on DED include establishing biological control agents against C. ulmi. In this report we describe the inhibitory action of the antibiotic polymyxin B on the causal agent of DED.In screening a number of antibiotics against C. ulmi, we observed that filter paper discs containing 300 units (U) of polymyxin B (Difco Laboratories) per disc, produced zones of inhibition to the fungus grown on potato dextrose agar or Sabouraud agar plates (100mm x 15mm), Fig. 1a. Total inhibition of fungal growth on a plate occurred when agar overlays containing fungus and antibiotic (polymyxin B sulfate, ICN Pharmaceuticals, Inc.) were poured on the underlying agar growth medium. The agar overlays consisted of the following: 4.5 ml of 0.7% agar, 0.5 ml of fungus (control plate); 4.0 ml of 0.7% agar, 0.5 ml of fungus, 0.5 ml of polymyxin B sulfate (77,700 U). Fig. 1, b and c, compares a control plate and polymyxin plate after seven days.


2020 ◽  
Vol 26 (1) ◽  
pp. 93-99
Author(s):  
Munekazu Kishimoto ◽  
Kazuo Nakamura ◽  
Takuto Tasaki ◽  
Kinya Matsumoto ◽  
Rina Nakano ◽  
...  

2019 ◽  
Vol 4 ◽  
pp. 203-218
Author(s):  
I.N. Kusnetsova ◽  
◽  
I.U. Shalygina ◽  
M.I. Nahaev ◽  
U.V. Tkacheva ◽  
...  

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 476e-476
Author(s):  
Craig S. Charron ◽  
Catherine O. Chardonnet ◽  
Carl E. Sams

The U.S. Clean Air Act bans the use of methyl bromide after 2001. Consequently, the development of alternative methods for control of soilborne pathogens is imperative. One alternative is to exploit the pesticidal properties of macerated tissues of Brassica spp. This study tested the potential of several Brassica spp. for control of fungal pathogens. Pythium ultimum Trow or Rhizoctonia solani Kühn plugs on potato-dextrose agar on petri dishes were sealed in 500-ml glass jars (at 22 °C) containing macerated leaves (10 g) from one of six Brassica spp. Radial growth was measured 24, 48, and 72 h after inoculation. Indian mustard (B. juncea) was the most suppressive, followed by `Florida Broadleaf' mustard (B. juncea). Volatile compounds in the jars were sampled with a solid-phase microextraction device (SPME) and identified by gas chromatography-mass spectrometry (GC-MS). Allyl isothiocyanate (AITC) comprised over 90% of the total volatiles measured from Indian mustard and `Florida Broadleaf' mustard. Isothiocyanates were detected in jars with all plants except broccoli. (Z)-3-hexenyl acetate was emitted by all plants and was the predominant volatile of `Premium Crop' broccoli (B. oleracea L. var. italica), `Michihili Jade Pagoda' Chinese cabbage (B. pekinensis), `Charmant' cabbage (B. oleracea L. var. capitata), and `Blue Scotch Curled' kale (B. oleracea L. var. viridis). To assess the influence of AITC on radial growth of P. ultimum and R. solani, AITC was added to jars to give headspace concentrations of 0.10, 0.20, and 0.30 mg·L–1 (mass of AITC per volume of headspace). Growth of both fungi was inhibited by 0.10 mg·L–1 AITC. 0.20 mg·L–1 AITC was fungicidal to P. ultimum although the highest AITC level tested (0.30 mg·L–1) did not terminate R. solani growth. These results indicate that residues from some Brassica spp. may be a viable part of a soilborne pest control strategy.


2004 ◽  
Vol 4 (4) ◽  
pp. 175-182 ◽  
Author(s):  
K. Rojek ◽  
F.A. Roddick ◽  
A. Parkinson

Phanerochaete chrysosporium was shown to rapidly decolorise a solution of natural organic matter (NOM). The effect of various parameters such as carbon and nitrogen content, pH, ionic strength, NOM concentration and addition of Mn2+ on the colour removal process was investigated. The rapid decolorisation was related to fungal growth and biosorption rather than biodegradation as neither carbon nor nitrogen limitation, nor Mn2+ addition, triggered the decolorisation process. Low pH (pH 3) and increased ionic strength (up to 50 g L‒1 added NaCl) led to greater specific removal (NOM/unit biomass), probably due to increased electrostatic bonding between the humic material and the biomass. Adsorption of NOM with viable and inactivated (autoclaved or by sodium azide) fungal pellets occurred within 24 hours and the colour removal depended on the viability, method of inactivation and pH. Colour removal by viable pellets was higher under the same conditions, and this, combined with desorption data, confirmed that fungal metabolic activity was important in the decolorisation process. Overall, removals of up to 40–50% NOM from solution were obtained. Of this, removal by adsorption was estimated as 60–70%, half of which was physicochemical, the other half metabolically-dependent biosorption and bioaccumulation. The remainder was considered to be removed by biodegradation, although some of this may be ascribed to bioaccumulation and metabolically-dependent biosorption.


1998 ◽  
Vol 37 (1) ◽  
pp. 155-162
Author(s):  
Flemming Schlütter ◽  
Kjeld Schaarup-Jensen

Increased knowledge of the processes which govern the transport of solids in sewers is necessary in order to develop more reliable and applicable sediment transport models for sewer systems. Proper validation of these are essential. For that purpose thorough field measurements are imperative. This paper renders initial results obtained in an ongoing case study of a Danish combined sewer system in Frejlev, a small town southwest of Aalborg, Denmark. Field data are presented concerning estimation of the sediment transport during dry weather. Finally, considerations on how to approach numerical modelling is made based on numerical simulations using MOUSE TRAP (DHI 1993).


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