ChemInform Abstract: Mucor piriformis, an Efficient N-Dealkylating Reagent for Thebaine and Its N-Variants.

Biotransformation of piperitenone (I), 5,5-dimethyl-2-(1-methylethylidene)-cyclohexanone (II), and 2-(1-ethyl-1-propylidene)-5-methylcyclohexanone (III) was studied using a versatile fungal strain, Mucor piriformis. The organism initiates transformation of these compounds by hydroxylation at the allylic positions or at the tertiary carbon. Transformation of piperitenone (I) by this strain yielded 5-hydroxypiperitenone (Ic), 7-hydroxypiperitenone (Id), 7-hydroxypulegone (Ie), 10-hydroxypiperitenone (If), and 4-hydroxypiperitenone (Ig) as metabolites. It was possible to block some of the metabolic activities of the organism through structural modification of piperitenone (I). This was evidenced by the fact that biotransformation of 5,5-dimethyl-2-(1-methylethylidene)-cyclohexanone (II) yielded 5,5-dimethyl-2-(1-hydroxy-1-methylethyl)-2-cyclohexen-1-one (IIb) and 5,5-dimethyl-3-hydroxy-2-(1-methylethylidene)-cyclohexanone (IIa), whereas 2-(1-ethyl-1-propylidene)-5-methylcyclohexanone (III) yielded 6-(1-ethyl-1-propylidene)-5-methyl-2-cyclohexen-1-one (IIIb) and 6-(1-ethyl-1-propylidene)-5-hydroxy-5-methylcyclohexanone (IIIa) as metabolites. Based on the identification of the metabolites, pathways for the biotransformation of I, II, and III have been proposed. The mode of biotransformation of these compounds by M. piriformis also compared to their modes of metabolism in the rat system.Key words: piperitenone, monoterpene ketone, biotransformation, fungal system, metabolites.

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Mating Types of Mucor Piriformis Isolated From Soil and Pear Fruit in Oregon Orchards (On The Life History Of Mucor Piriformis)

Mycologia ◽

10.1080/00275514.1986.12025320 ◽

1986 ◽

Vol 78 (5) ◽

pp. 766-770 ◽

Cited By ~ 7

Author(s):

Themis J. Michailides ◽

Robert A. Spotts

Keyword(s):

Life History ◽

Mating Types ◽

Pear Fruit ◽

History Of ◽

Mucor Piriformis

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Variability in Postharvest Decay Among Apple Cultivars

Plant Disease ◽

10.1094/pdis.1999.83.11.1051 ◽

1999 ◽

Vol 83 (11) ◽

pp. 1051-1054 ◽

Cited By ~ 48

Author(s):

R. A. Spotts ◽

L. A. Cervantes ◽

E. A. Mielke

Keyword(s):

Botrytis Cinerea ◽

Fungal Pathogens ◽

Decay Resistance ◽

The Other ◽

Penicillium Expansum ◽

Epidermal Layer ◽

Apple Industry ◽

Mucor Piriformis ◽

Apple Cultivars ◽

Potential Decay

The level of resistance to decay caused by four fungal pathogens, the force required to break the epidermis, and the extent of open sinuses as measures of potential decay resistance were determined for the fruit of several apple cultivars. No single cultivar was the most resistant to each of the four pathogens in this study. In addition, each cultivar that was the most resistant to one pathogen also was the most susceptible to one of the other pathogens. However, Royal Gala was the most resistant to the wound pathogens Botrytis cinerea, Penicillium expansum, and Mucor piriformis. Fuji and Oregon Spur II were more resistant than other cultivars to Pezicula malicorticis. The epidermis (skin) of Fuji and Granny Smith were the most resistant to puncture, requiring an average of 81.5 and 87.0 Newtons, respectively, to break the epidermal layer. Fuji had the highest percentage of fruits with open sinuses, with a mean of 38%, whereas Braeburn had 0% of fruit with open sinuses. The cultivar information presented herein may be a valuable measure of decay resistance and may be of use to the apple industry.

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Survival of Mucor piriformis in Soil of Apple Orchards in California

Plant Disease ◽

10.1094/pdis.1999.83.2.189 ◽

1999 ◽

Vol 83 (2) ◽

pp. 189-193 ◽

Cited By ~ 2

Author(s):

Li-Yun Guo ◽

Themis J. Michailides ◽

David P. Morgan

Keyword(s):

Mating Type ◽

Apple Fruit ◽

Early Spring ◽

Causal Agent ◽

Mating Types ◽

Apple Orchards ◽

Mucor Piriformis ◽

Dry Soil

Four apple orchards were sampled periodically in 1995 and 1996 to determine the population levels of Mucor piriformis, the causal agent of Mucor rot. The highest population, 119 propagules of M. piriformis per g of dry soil, occurred during winter. Populations declined during summer and fall and increased again in winter and early spring of the following year. Isolates from soil and apple fruit of these orchards contained +, −, and neuter mating types, with the + being the predominant mating type. Depending on the orchard, up to 27.7% of apples infected by M. piriformis had zygospores developed on them. The time of increase in M. piriformis populations corresponded with postharvest drop and decay of apples on the orchard floor. Experiments were carried out to compare changes in M. piriformis populations in soil with intact fruit left on the orchard floor, sliced fruit, or after removal of fruit from the orchard. The greatest numbers of M. piriformis occurred in soil with apple pieces, followed by soil with intact apples, and the lowest in soil without apples. Results suggest that the best time to sample soils to determine the occurrence of M. piriformis in California apple orchards is from January to March, and practices of flail-mowing the orchard floor after harvest may increase population levels of M. piriformis in soil.

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Germination of Zygospores of Mucor piriformis (On the Life History of Mucor piriformis)

Mycologia ◽

10.2307/3807563 ◽

1988 ◽

Vol 80 (6) ◽

pp. 837 ◽

Cited By ~ 6

Author(s):

Themis J. Michailides ◽

Robert A. Spotts

Keyword(s):

Life History ◽

History Of ◽

Mucor Piriformis

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Improved Detection of Polygalacturonase Activity due to Mucor piriformis with a Modified Dinitrosalicylic Acid Reagent

Phytopathology ◽

10.1094/phyto.1997.87.2.161 ◽

1997 ◽

Vol 87 (2) ◽

pp. 161-163 ◽

Cited By ~ 19

Author(s):

Guangyi Wang ◽

Themis J. Michailides ◽

Richard M. Bostock

Keyword(s):

Sodium Hydroxide ◽

Fungal Pathogen ◽

Galacturonic Acid ◽

Sodium Sulfite ◽

Limit Of Detection ◽

Mucor Piriformis ◽

Acid Reagent ◽

Polygalacturonase Activity ◽

Higher Sensitivity

An assay for determination of galacturonic acid with 3,5-dinitrosalicylic acid was developed that substantially extends the linear range of detection compared to a previously published method with this reagent. In the improved assay, galacturonic acid was detected with a reagent containing 44 mM 3,5-dinitrosalicylic acid, 4 mM sodium sulfite, and 375 mM sodium hydroxide. The absorbance of the solution after reaction with galacturonic acid was determined at 575 nm and was linear at concentrations of galacturonic acid up to 50 μmol, with a lower limit of detection at ~400 nmol. The assay with the improved reagent could be performed in wavelength ranges from 550 to 575 nm, with higher sensitivity at the shorter wavelengths. The new reagent was used in routine assays of polygalacturonase activity in culture filtrates of the important postharvest fungal pathogen Mucor piriformis.

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