Compartmentalization in Penicillin G Biosynthesis by Penicillium chrysogenum PQ-96

Abstract

The arrangement of organelles in the sub-apical productive non-growing vacuolated hyphal cells of the high- and the low-penicillin-pro- ducing strains Penicillium chrysogenum was compared using transmission electron microscopy. In the productive cells of the high-yielding strain the endoplasmic reticulum and the polyribosomes with associated peroxisomes are frequently arranged at the periphery of the cytoplasm and around the vacuoles. At the high activity of penicillin G biosynthesis the immuno-label of the cytosolic isopenicillin N synthase is concentrated at the polyribosomes arranged in the peripheral cytoplasm and along the tonoplast as well as around the peroxisomes. On the basis of the obtained results the compartmentalization of the pathway of penicillin G biosymthesis is discussed. The obtained results support the phenylacetic acid detoxification hypothesis of penicillin G biosynthesis.

Pexophagy in Penicillin G Secretion by Penicillium chrysogenum PQ-96

“…The examined strains were grown in complex media (Kurzątkowski et al, 2014a) and the antibiotic assay was carried out as described previously (GarciaEstrada et al, 2007). The preparation for transmission electron microscopy and immunoelectron microscopy was performed as described previously (Kurzątkowski et al, 2014a). The ultrathin sections were examined under a transmission electron microscope JEOL, JEM 1220 (Tokyo, Japan).…”

New Data On Isopenicillin N Synthase And Peroxisome Co-Location In The Hyphal Cells Of Penicillium Chrysogenum PQ-96 – Pexophagy And Exocytosis

“…In contrast to the nucleus, mitochondria, or chloroplasts, peroxisomes do not contain DNA. Proliferation by division of preexisting organelles and the role of endoplasmic reticulum in the biogenesis of these organelles is now well established [11,15,16]. Mitochondria are also involved in the biogenesis of the peroxisomal membrane [23].…”

“…These organelles accumulate toxic metabolites and act as a barrier protecting the cytosol from the hazardous compounds by degrading of toxic metabolites. Peroxisome acts as a waste furnace of toxic organic compounds, where they are oxidated, and secreted out of the cells coupled to carrier molecules [18] or in industrial amounts by pexophage and exocytosis [11,15,16]. A good example is the process of penicillin G biosynthesis and its secretion from the mycelial cells of P. chrysogenum into the fermentation broth.…”

“…It was also suggested that the large peroxisomes abundantly arranged at the periphery of the cytoplasm (Fig. 2C) seem to build a PA-barrier protecting the hyphal cells from the toxicity of the precursor of penicillin G biosynthesis [15,16]. Based on electron microscopy and biochemical data, there are now solid evidences con-firming that IAT and PA are cumulated in peroxisomes [18].…”

Antibiotic biosynthesis and secondary metabolism in high-yielding strains of Streptomyces, Penicillium chrysogenumand Acremonium chrysogenum

“…Overexpression of the peroxisome proliferation gene pex11 in P. chrysogenum results in an increase of both peroxisome numbers and in the activity of penicillin biosynthesis. The productive mycelia cells of high penicillin G producing strains show increasing numbers of large peroxisomes mainly at the period of the intensive antibiotic biosynthesis [1,6,7,22,24,25]. De novo synthesis of peroxisomes and collo-cation of large peroxisomes with vacuole as well as pero xisomes multiplication by fission are significant features of the high productive non-growing mycelial cells.…”