Kinetics of Filamentous Growth and Branching

Prosser, James I.

doi:10.1007/978-0-585-27576-5_14

Cited by 53 publications

(33 citation statements)

References 45 publications

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“…2) and there was no difference in the specific ␣-amylase production. Differences in the length of time mycelia were subject to shear stresses, differences in specific growth rates and the effects of autolysis (in fed-batch culture) are thought to account for some of the differences observed in G between different culture systems (Smith et al, 1990;van Suijdam and Metz, 1981;Prosser, 1995). Withers et al (1994) have also observed that G values may differ considerably depending on the culture system employed.…”

Section: Discussionmentioning

confidence: 93%

Effect of branch frequency inAspergillus oryzae on protein secretion and culture viscosity

Bocking

Wiebe

Robson

et al. 1999

Biotechnol. Bioeng.

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Section: Discussionmentioning

confidence: 93%

Effect of branch frequency inAspergillus oryzae on protein secretion and culture viscosity

Bocking

Wiebe

Robson

et al. 1999

Biotechnol. Bioeng.

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“…The decline in expression of the GUS gene, controlled by a heterologous constitutive promoter, is to be expected as the mycelium enters stationary phase. Stationary phase, triggered through changes in the environment such as nutrient limitation, pH changes, or the accumulation of waste products (27), is accompanied in fungi and other organisms by reduced protein synthesis, even though specific pathways, such as secondary metabolite pathways, might become more active (1,4,8,9,24,30,36,41,43,44). In other words, in culture N. lolii biomass increase, through hyphal apical extension, and metabolic activity are correlated and linked.…”

Section: Discussionmentioning

confidence: 99%

“…In culture, cessation or slowing of biomass increase and hyphal extension in fungi occurs when environmental conditions curtail metabolic activity (1,27). We wanted to investigate whether, in planta, the cessation of extension of N. lolii hyphae coincides with, or is brought about by, a curtailing of metabolic activity.…”

Section: Vol 67 2001 Fungal Growth Regulation In Endophytes 5379mentioning

confidence: 99%

In Planta Regulation of Extension of an Endophytic Fungus and Maintenance of High Metabolic Rates in Its Mycelium in the Absence of Apical Extension

Tan¹,

Spiering²,

Scott³

et al. 2001

Appl Environ Microbiol

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The fungus Neotyphodium lolii is an endophytic symbiont. It grows in the intercellular spaces of the perennial ryegrass Lolium perenne, producing secondary metabolites which enhance the fitness of the association over that of uninfected L. perenne. We report that the average number of hyphal strands in a given section of a leaf remains constant during the life of a leaf, indicating synchrony of leaf and hyphal extension, including cessation of hyphal extension when leaf extension ceases. We used a constitutively expressed reporter gene as an indicator of the mycelium's metabolic activity during and after hyphal extension. Reporter gene activity decreased when the mycelium stopped extending in liquid culture but not in planta. This indicates that in planta endophyte hyphae remain metabolically highly active when extension has ceased and throughout the life of the leaf they are colonizing. The behavior of the fungus in planta indicates the existence of signaling pathways which (i) synchronize the extension of leaf and hypha by regulating hyphal extension, (ii) suppress hyphal branching, and (iii) stop apical extension of fungal hyphae, without reducing the mycelium's metabolic activity. These signals may be crucial for the symbiosis, by allowing the endophyte to switch the focus of its metabolic activity from extension to the production of secondary metabolites.Neotyphodium endophytes are mutualistic symbionts of grasses, living in their intercellular spaces. Their presence confers upon the grass a number of physiological characteristics such as drought resistance, enhanced growth, and protection from herbivores, through the synthesis of feeding deterrents and toxins. In return, the plant provides nutrients and propagates the endophyte via its seeds (17,28,34,35,46,47).We have recently used a Neotyphodium endophyte, transformed with the Escherichia coli ␤-glucuronidase gene (GUS reporter gene system [14]), under the control of a heterologous constitutive promoter, to estimate the in planta distribution of endophyte metabolic activity (as GUS activity) (12). We found that GUS activity followed well-defined patterns, established during the growth of ryegrass leaves (12). The endophyte metabolic activity in plant tissue measured in such experiments depends on (i) the number of endophyte hyphae present, (ii) the rate of gene expression in these hyphae, and (iii) the half-life of the GUS enzyme. Thus, while the existence of these patterns was intriguing, these experiment allowed only limited conclusions as to how they are generated. We have now determined directly the in planta distribution of endophyte hyphal biomass. In parallel, we have determined the endophyte's constitutive GUS expression in the same ryegrass tillers. We have also determined GUS activity in exponentially growing and stationary laboratory cultures of the same endophyte strain. Together, these data allow us to draw conclusions regarding the endophyte's metabolic state in different parts of the ryegrass tiller. MATERIALS AND METHODSStrains and plant ...

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“…1) and the formation of branches along the existing hyphae 43,66) . The process of fungal growth is controlled by molecular mechanisms involving many gene products 44,45,52,53,62) .…”

Section: Fungal Cellular Morphologymentioning

confidence: 99%

Scientific Advances with Aspergillus Species that Are Used for Food and Biotech Applications

Biesebeke

Record²

2008

Microb. Environ.

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Yeast and filamentous fungi have been used for centuries in diverse biotechnological processes. Fungal fermentation technology is traditionally used in relation to food production, such as for bread, beer, cheese, sake and soy sauce. Last century, the industrial application of yeast and filamentous fungi expanded rapidly, with excellent examples such as purified enzymes and secondary metabolites (e.g. antibiotics), which are used in a wide range of food as well as nonfood industries. Research on protein and/or metabolite secretion by fungal species has focused on identifying bottlenecks in (post-) transcriptional regulation of protein production, metabolic rerouting, morphology and the transit of proteins through the secretion pathway. In past years, genome sequencing of some fungi (e.g. Aspergillus oryzae, Aspergillus niger) has been completed. The available genome sequences have enabled identification of genes and functionally important regions of the genome. This has directed research to focus on a post-genomics era in which transcriptomics, proteomics and metabolomics methodologies will help to explore the scientific relevance and industrial application of fungal genome sequences.

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Kinetics of Filamentous Growth and Branching

Cited by 53 publications

References 45 publications

Effect of branch frequency inAspergillus oryzae on protein secretion and culture viscosity

Effect of branch frequency inAspergillus oryzae on protein secretion and culture viscosity

In Planta Regulation of Extension of an Endophytic Fungus and Maintenance of High Metabolic Rates in Its Mycelium in the Absence of Apical Extension

Scientific Advances with Aspergillus Species that Are Used for Food and Biotech Applications

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