Growth and Function of Fungal Mycelia in Heterogeneous Environments

Abstract

As decomposer organisms, pathogens, plant symbionts and nutrient cyclers, fungi are of fundamental importance in the terrestrial environment. Moreover, in addition to their well-known applications in industry, many species also have great potential in environmental biotechnology. The study of this important class of organisms is difficult through experimental means alone due to the heterogeneity of their natural growth habitat and the microscopic scale of growth. In this work we present a mathematical model for colony expansion that is derived through consideration of the growth characteristics on the microscale. The model equations are of mixed hyperbolic-parabolic type and are treated with a numerical scheme that preserves positivity and conserves mass. The numerical solutions are compared against experimental results in a variety of environments. Thus the effect of different translocation mechanisms on fungal growth and function are identified. The derivation and analysis of an approximation to the full model yields further results concerning basic properties of mycelial growth. Finally, the acidification of the growth habitat is considered and the model thus provides important predictions on the functional consequences of the redistribution of internally-located material.

Polissacarídeos de parede celular fúngica: purificação e caracterização

“…No ambiente terrestre, os fungos têm um papel importante nos ciclos biogeoquímicos do carbono, nitrogênio ou fósforo (BOSwELL et al, 2003). Como fitopatógenos, estes organismos possuem mecanismos de adesão ao hospedereiro, onde as moléculas de reconhecimento e união são, na maior parte dos casos, de natureza protéica ou glicoprotéica (SUGUI; LEITE; NICHOLSON, 1998;XIAO et al, 1994) e, por isso, a produção de proteínas e polissacarídeos extracelulares têm sido associadas à capacidade do microrganismo causar doenças em plantas (DOSS, 1999;GIL-AD;BAR-NUN;MAYER, 2001;LEITE et al, 2001).…”

“…O crescimento micelial é dependente do processo de translocação, onde o material celular é direcionado para as regiões em desenvolvimento (BOSWELL et al, 2003), permitindo a formação das estruturas celulares, como a parede, e com isso facilitando a ocupação dos ambientes pelo microrganismo. Em condições normais de desenvolvimento, a estrutura da parede celular é baseada na parede já existente nas células progenitoras, que são extendidas e remodeladas.…”

Uncertainty Quantification Driven Predictive Multi-Scale Model for Synthesis of Mycotoxins

“…Using the process of dichotomous and lateral branching [5], hyphae create the mycelial network, in which the older branches eventually collides with existing braches and annihilated by the process of anastomosis [6]. The nutrients are internalized by the hyphae [7][8][9][10] and are sent through the mycelial network to the area of high nutrient demand, using a process called translocation [8,11,12].As hyphae propagate, they leave behind a stationary biomass [13]that consists of older cells, which are structurally stable and promote further growth of the hyphae. Earlier studies with mycotoxin producers suggest that mycotoxin production promoteshyphal growth and vice-versa.…”

Applying dimorphic yeasts as model organisms to study mycelial growth: Part 1. Experimental investigation of the spatio-temporal development of filamentous yeast colonies

“…This is mainly because changes in the physiological state of individual fungal cells, as well as nutrient translocation inside the hyphae and in the growth substrate, respectively, are processes that are extremely hard to monitor which leaves considerable uncertainties in the interpretation of the experimental data. In this context, the use of mathematical models for the investigation of mycelial growth gains increasing attention [9][10][11][12][13]. Using the abstractive power of these models, it is not only possible to simulate the complex behaviour of fungal mycelia based on rather simple fundamental mechanisms or rules [14][15][16].…”