Role of proteases in autolysis of Penicillium chrysogenum chemostat cultures in response to nutrient depletion

2000 ◽  
Vol 53 (2) ◽  
pp. 235-242 ◽  
Author(s):  
M. McIntyre ◽  
D. R. Berry ◽  
B. McNeil
Keyword(s):  
Penicillium Chrysogenum ◽  
Nutrient Depletion ◽  
Chemostat Cultures

scholarly journals Impact of Altered Trehalose Metabolism on Physiological Response of Penicillium chrysogenum Chemostat Cultures during Industrially Relevant Rapid Feast/Famine Conditions

Processes ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 118
Author(s):  
Xinxin Wang ◽  
Jiachen Zhao ◽  
Jianye Xia ◽  
Guan Wang ◽  
Ju Chu ◽  
...  
Keyword(s):  
Penicillium Chrysogenum ◽  
Production Capacity ◽  
Penicillin Biosynthesis ◽  
Quantitative Metabolomics ◽  
Chemostat Cultures ◽  
Trehalose Metabolism ◽  
Extracellular Glucose ◽  
Metabolite Pool ◽  
Futile Cycles

Due to insufficient mass transfer and mixing issues, cells in the industrial-scale bioreactor are often forced to experience glucose feast/famine cycles, mostly resulting in reduced commercial metrics (titer, yield and productivity). Trehalose cycling has been confirmed as a double-edged sword in the Penicillium chrysogenum strain, which facilitates the maintenance of a metabolically balanced state, but it consumes extra amounts of the ATP responsible for the repeated breakdown and formation of trehalose molecules in response to extracellular glucose perturbations. This loss of ATP would be in competition with the high ATP-demanding penicillin biosynthesis. In this work, the role of trehalose metabolism was further explored under industrially relevant conditions by cultivating a high-yielding Penicillium chrysogenum strain, and the derived trehalose-null strains in the glucose-limited chemostat system where the glucose feast/famine condition was imposed. This dynamic feast/famine regime with a block-wise feed/no feed regime (36 s on, 324 s off) allows one to generate repetitive cycles of moderate changes in glucose availability. The results obtained using quantitative metabolomics and stoichiometric analysis revealed that the intact trehalose metabolism is vitally important for maintaining penicillin production capacity in the Penicillium chrysogenum strain under both steady state and dynamic conditions. Additionally, cells lacking such a key metabolic regulator would become more sensitive to industrially relevant conditions, and are more able to sustain metabolic rearrangements, which manifests in the shrinkage of the central metabolite pool size and the formation of ATP-consuming futile cycles.

scholarly journals An early intermediate in the biosynthesis of biotin: Incorporation studies with [1,7-14C2]pimelic acid

1966 ◽  
Vol 101 (3) ◽  
pp. 601-606 ◽  
Author(s):  
M A Eisenberg ◽  
R Maseda
Keyword(s):  
Penicillium Chrysogenum ◽  
Pimelic Acid ◽  
Culture Filtrates ◽  
High Yields ◽  
Intermediate Role

1. An unknown biotin vitamer was obtained in high yields in culture filtrates of Penicillium chrysogenum. 2. Production of this vitamer and desthiobiotin is controlled by the biotin concentration in the medium. 3. The unknown vitamer becomes labelled when the organism is grown in the presence of radioactive pimelic acid. 4. Chromatographic procedures were developed for the purification of the radioactive vitamer. 5. The vitamer is extremely stable in concentrated acid but gives rise to new vitamers under certain conditions. 6. The intermediate role of this vitamer in the synthesis of biotin is discussed.

scholarly journals Investigating the Role of Shape and Size of Gold Nanoparticles on Their Toxicities to Fungi

2018 ◽  
Author(s):  
Kangze Liu ◽  
Zhonglei He ◽  
Hugh J. Byrne ◽  
James Curtin ◽  
Furong Tian
Keyword(s):  
Gold Nanoparticles ◽  
Penicillium Chrysogenum ◽  
Survival Rates ◽  
Relative Survival ◽  
Toxicity Assessment ◽  
Mucor Hiemalis ◽  
Wide Range ◽  
Living Organisms ◽  
Shape And Size

The possibility of releasing gold nanoparticles (GNP) into the environment has been rapidly increasing with the wide spread and flourishing application of gold nanoparticles (GNPs) in a wide range of areas. Consequently, environmental effects of GNP, especially toxicities to living organisms have drawn great attention. However, their toxicological characteristics still remain unclear. Fungi, as the decomposers of the ecosystem, interact directly with the environment and critically control the overall health of the biosphere. Thus, their sensitivity to GNP toxicity is particularly important. The aim of this study was to evaluate the role of shape and size of GNPs on their toxicities to fungi, which could help reveal the ecotoxicity of GNPs. Aspergillus niger, Mucor hiemalis and Penicillium chrysogenum were chosen for toxicity assessment, and circular and star/flower-shaped GNPs sized from 0.7 nm to large aggregates of 400 nm have been synthesised. After mixed with GNPs and reacting agents of GNPs accordingly and incubated for 48 hours, the relative survival rates of each kind of fungus was calculated and compared. The results indicated that with similar sizes, star/flower-shaped GNPs are more toxic to fungi than circular-shaped GNPs; the toxicity of star/flower-shaped GNPs increases with smaller sizes. The results also showed that different species of fungus reacts differently to same GNPs, and Penicillium chrysogenum was relatively more sensitive under the exposure to GNPs.

scholarly journals Resolving Phenylalanine Metabolism Sheds Light on Natural Synthesis of Penicillin G in Penicillium chrysogenum

2011 ◽  
Vol 11 (2) ◽  
pp. 238-249 ◽  
Author(s):  
Tânia Veiga ◽  
Daniel Solis-Escalante ◽  
Gabriele Romagnoli ◽  
Angela ten Pierick ◽  
Mark Hanemaaijer ◽  
...  
Keyword(s):  
Nitrogen Source ◽  
Transcriptome Analysis ◽  
Penicillium Chrysogenum ◽  
Penicillin G ◽  
Side Chain ◽  
Acid Decarboxylase ◽  
Content Type ◽  
Chemostat Cultures ◽  
Phenylpyruvate Decarboxylase ◽  
Dual Substrate

ABSTRACTThe industrial production of penicillin G byPenicillium chrysogenumrequires the supplementation of the growth medium with the side chain precursor phenylacetate. The growth ofP. chrysogenumwith phenylalanine as the sole nitrogen source resulted in the extracellular production of phenylacetate and penicillin G. To analyze this natural pathway for penicillin G production, chemostat cultures were switched to [U-13C]phenylalanine as the nitrogen source. The quantification and modeling of the dynamics of labeled metabolites indicated that phenylalanine was (i) incorporated in nascent protein, (ii) transaminated to phenylpyruvate and further converted by oxidation or by decarboxylation, and (iii) hydroxylated to tyrosine and subsequently metabolized via the homogentisate pathway. The involvement of the homogentisate pathway was supported by the comparative transcriptome analysis ofP. chrysogenumcultures grown with phenylalanine and with (NH4)2SO4as the nitrogen source. This transcriptome analysis also enabled the identification of two putative 2-oxo acid decarboxylase genes (Pc13g9300 and Pc18g01490). cDNAs of both genes were cloned and expressed in the 2-oxo-acid-decarboxylase-freeSaccharomyces cerevisiaestrain CEN.PK711-7C (pdc1 pdc5 pdc6Δ aro10Δ thi3Δ). The introduction of Pc13g09300 restored the growth of thisS. cerevisiaemutant on glucose and phenylalanine, thereby demonstrating that Pc13g09300 encodes a dual-substrate pyruvate and phenylpyruvate decarboxylase, which plays a key role in an Ehrlich-type pathway for the production of phenylacetate inP. chrysogenum. These results provide a basis for the metabolic engineering ofP. chrysogenumfor the production of the penicillin G side chain precursor phenylacetate.

scholarly journals Organization of the Pre-autophagosomal Structure Responsible for Autophagosome Formation

2008 ◽  
Vol 19 (5) ◽  
pp. 2039-2050 ◽  
Author(s):  
Tomoko Kawamata ◽  
Yoshiaki Kamada ◽  
Yukiko Kabeya ◽  
Takayuki Sekito ◽  
Yoshinori Ohsumi
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Ternary Complex ◽  
Nutrient Depletion ◽  
Autophagosome Formation ◽  
Yeast Saccharomyces Cerevisiae ◽  
Atg Proteins ◽  
Starvation Condition ◽  
Putative Site ◽  
Starvation Conditions

Autophagy induced by nutrient depletion is involved in survival during starvation conditions. In addition to starvation-induced autophagy, the yeast Saccharomyces cerevisiae also has a constitutive autophagy-like system, the Cvt pathway. Among 31 autophagy-related (Atg) proteins, the function of Atg17, Atg29, and Atg31 is required specifically for autophagy. In this study, we investigated the role of autophagy-specific (i.e., non-Cvt) proteins under autophagy-inducing conditions. For this purpose, we used atg11Δ cells in which the Cvt pathway is abrogated. The autophagy-unique proteins are required for the localization of Atg proteins to the pre-autophagosomal structure (PAS), the putative site for autophagosome formation, under starvation condition. It is likely that these Atg proteins function as a ternary complex, because Atg29 and Atg31 bind to Atg17. The Atg1 kinase complex (Atg1–Atg13) is also essential for recruitment of Atg proteins to the PAS. The assembly of Atg proteins to the PAS is observed only under autophagy-inducing conditions, indicating that this structure is specifically involved in autophagosome formation. Our results suggest that Atg1 complex and the autophagy-unique Atg proteins cooperatively organize the PAS in response to starvation signals.

scholarly journals Role of the ptsN Gene Product in Catabolite Repression of the Pseudomonas putida TOL Toluene Degradation Pathway in Chemostat Cultures▿

2006 ◽  
Vol 72 (11) ◽  
pp. 7418-7421 ◽  
Author(s):  
Isabel Aranda-Olmedo ◽  
Patricia Marín ◽  
Juan L. Ramos ◽  
Silvia Marqués
Keyword(s):  
Carbon Source ◽  
Pseudomonas Putida ◽  
Gene Product ◽  
Catabolite Repression ◽  
Maximum Rate ◽  
Degradation Pathway ◽  
Toluene Degradation ◽  
Batch Cultures ◽  
Chemostat Cultures

ABSTRACT The Pseudomonas putida KT2440 TOL upper pathway is repressed under nonlimiting conditions in cells growing in chemostat with succinate as a carbon source. We show that the ptsN gene product IIANtr participates in this repression. Crc, involved in yeast extract-dependent repression in batch cultures, did not influence expression when cells were growing in a chemostat with succinate at maximum rate.

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