own or other species. In this chapter, we review single and multiscale mathematical models proposed to investigate the dynamics of the biochemical warfare
between competing species for survival.
Keywords
allelochemical suppression · population dynamics · multiscale modelling ·
community assembly
1
Introduction
Microorganisms, such as bacteria [1], yeasts [2], and other fungi [3], frequently
secrete antibiotic compounds that kill or inhibit the growth of sensitive strains from
their own genotypes or different species. Similarly, plants commonly exude secondary metabolites (phytotoxins) that suppress the germination or growth of neighboring plants [4]. Amazingly, glycolytic carcinoma cells excrete large amounts of lactic
acid toxic to the surrounding normal cells. The resulting tissue acidification fosters
tumor growth and invasion [5]. In glioblastoma, the most aggressive brain tumor,
glioma cells release ATP to the tumor microenvironment. The extracellular ATP
itself has a small cytotoxic effect on normal cells, but adenosine formed from
ATP degradation by ectonucleotidases overexpressed on the membrane of glioma
cells induces significant apoptosis of the adjacent normal cells [6]. These examples
suggest that interference competitions mediated by the production of toxic chemical
compounds – antibiotic, phytotoxins, lactate, etc. – are ubiquitous in biological
communities.
Beyond its paramount relevance for understand microorganism and plant communities, the practical importance of antibiotics and other secondary metabolites is
tremendous. Indeed, some exotic invasive plants may use allelopathic suppression to
disrupt inherent, coevolved interactions among long-associated native species constituting the communities they invade [7]. This worldwide phenomenon represents
a major threat for ecosystems functioning and biodiversity conservation, water
availability, and agricultural production [8–11]. Preventing biological invasions
and predicting their spreading patterns emerge as imperative tasks in an ecologically
sustainable world. Also, a major problem in public health is the invasion of the
human organism by some of their symbiont microbes eventually causing serious
diseases, as is the case of Enterococcus faecalis, a leading cause of hospital-acquired
infections [12, 13]. The inter- and intraspecies competition among the Enterobacteriaceae in the inflamed gut is mediated by microcins [14]. Moreover, microcins can
act as narrow-spectrum therapeutics to inhibit enteric pathogens and reduce enterobacterial blooms [14].
From the mathematical point of view, patterns of biological invasion are interesting examples of spontaneous symmetry breaking in complex systems.
The spreading of an alien species from the place where it has been originally
introduced in the habitat (local invasion) can progress in various ways. In a homogeneous environment, invasion frequently generates smooth stationary traveling
468
S. A. Carvalho and M. L. Martins
between competing species for survival.
Keywords
allelochemical suppression · population dynamics · multiscale modelling ·
community assembly
1
Introduction
Microorganisms, such as bacteria [1], yeasts [2], and other fungi [3], frequently
secrete antibiotic compounds that kill or inhibit the growth of sensitive strains from
their own genotypes or different species. Similarly, plants commonly exude secondary metabolites (phytotoxins) that suppress the germination or growth of neighboring plants [4]. Amazingly, glycolytic carcinoma cells excrete large amounts of lactic
acid toxic to the surrounding normal cells. The resulting tissue acidification fosters
tumor growth and invasion [5]. In glioblastoma, the most aggressive brain tumor,
glioma cells release ATP to the tumor microenvironment. The extracellular ATP
itself has a small cytotoxic effect on normal cells, but adenosine formed from
ATP degradation by ectonucleotidases overexpressed on the membrane of glioma
cells induces significant apoptosis of the adjacent normal cells [6]. These examples
suggest that interference competitions mediated by the production of toxic chemical
compounds – antibiotic, phytotoxins, lactate, etc. – are ubiquitous in biological
communities.
Beyond its paramount relevance for understand microorganism and plant communities, the practical importance of antibiotics and other secondary metabolites is
tremendous. Indeed, some exotic invasive plants may use allelopathic suppression to
disrupt inherent, coevolved interactions among long-associated native species constituting the communities they invade [7]. This worldwide phenomenon represents
a major threat for ecosystems functioning and biodiversity conservation, water
availability, and agricultural production [8–11]. Preventing biological invasions
and predicting their spreading patterns emerge as imperative tasks in an ecologically
sustainable world. Also, a major problem in public health is the invasion of the
human organism by some of their symbiont microbes eventually causing serious
diseases, as is the case of Enterococcus faecalis, a leading cause of hospital-acquired
infections [12, 13]. The inter- and intraspecies competition among the Enterobacteriaceae in the inflamed gut is mediated by microcins [14]. Moreover, microcins can
act as narrow-spectrum therapeutics to inhibit enteric pathogens and reduce enterobacterial blooms [14].
From the mathematical point of view, patterns of biological invasion are interesting examples of spontaneous symmetry breaking in complex systems.
The spreading of an alien species from the place where it has been originally
introduced in the habitat (local invasion) can progress in various ways. In a homogeneous environment, invasion frequently generates smooth stationary traveling
468
S. A. Carvalho and M. L. Martins