Soft rot in apple caused by Rhizopus oryzae was found for the first time in Korea. A detailed description of the specimen is given along with its internal transcribed spacer rDNA sequence. The fungus was identified as Rhizopus oryzae based on the mycological characteristics, molecular data, and pathogenicity testing.
DNA, Ribosomal ; Fungi ; Korea ; Oryza ; Rhizopus

Rhizopus oryzae is reported for the first time on Cucumis melo L. var. makuwa Makino. A detailed description of this Korean specimen is given, along with its rDNA internal transcribed spacer sequence. On the basis of mycological characteristics and molecular data, the fungus was identified as R. oryzae Went & Prinsen Geerligs.
Cucumis ; Cucumis melo ; DNA, Ribosomal ; Fungi ; Oryza ; Rhizopus

Soft rot on banana fruit caused by Rhizopus oryzae was identified for the first time in Korea. Colonies were white to light brown and formed numerous sporangiospores. Optimum temperature for mycelial growth was 30degrees C. Sporangia were globose and 30~200 microm. Sporangiophores were usually straight, 8~20 microm, and rhizoids usually in groups of 3~5. Columella were globose to sub-globose and 90~110 microm. Sporangiospores were sub-globose or oval and 4~10 microm. Based on its mycological characteristics, molecular analysis, and pathogenicity to host plants, this fungus was identified as Rhizopus oryzae Went & Prisen Geerligs. This is the first report of soft rot on banana caused by Rhizopus oryzae in Korea.
Fruit ; Fungi ; Humans ; Korea ; Light ; Musa ; Oryza ; Rhizopus ; Sporangia

Mucormycosis is an opportunistic fungal infection frequently associated with diabetes mellitus or an immunocompromised status. Rhinocerebral mucormycosis, the most frequent form of mucormycosis, is characterized by facial pain, swelling, fever, blood-tinged rhinorrhea and shows a rapidly progressive course. Herein, we describe an immunocompromised and diabetic woman with rhinocerebral mucormycosis initially misdiagnosed as herpes zoster.
Diabetes Mellitus ; Facial Pain ; Female ; Fever ; Herpes Zoster* ; Humans ; Mucormycosis* ; Rhizopus

Rhizopus soft rot caused by Rhizopus stolonifer occurred on pears (Pyrus serotina) in the Jinju City Agricultural Products Wholesale Market in Korea from 2004 to 2005. The infection usually started from wounds due to cracking at harvest time. The lesions started as water-soaked, rapidly softened, then gradually expanded. The mycelia grew vigorously on the surface of the fruits and formed stolons. Colonies on potato dextrose agar at 25degrees C were white cottony to brownish black. Sporangia were globose, black and 90~120 microm in size. Sporangiophores were light brown and 480~2600 x 12~18 microm in size. Sporangiospores were globose to oval, brownish, streaked, and 8~14 x 6~10 microm in size. Columella were light brownish gray, hemispherical and 70~80 microm in size. On the basis of these symptoms, mycological characteristics and pathogenicity tests on host plants, the fungus was identified as Rhizopus stolonifer (Ehrenb.) Vuill. This is the first report of rhizopus soft rot on pear (P. serotina) caused by R. stolonifer in Korea.
Agar ; Fruit ; Fungi ; Glucose ; Gyeongsangnam-do ; Korea* ; Pyrus* ; Rhizopus* ; Solanum tuberosum ; Sporangia ; Virulence ; Wounds and Injuries

Different strains of mold were screened for the production of high quality Korean traditional rice wine with anti-hypertension and good acceptability. We isolated 867 nuruk mold strains and selected 24 for further study based on measurement of amylase activity. Among them, mold No. 17 showed high ethanol production upon fermentation with Saccharomyces cerevisiae as well as anti-hypertensive properties. The No. 17 strain was therefore selected as the functional mold and later identified as Rhizopus stolonifer based on molecular biological characteristics. Optimal fermentation conditions for the brewing of anti-hypertensive traditional rice wine comprised the addition of R. stolonifer No. 17 koji at a concentration of 35 sp/g and a fermentation period of 10 days at 25degrees C using S. cerevisiae.
Amylases ; Ethanol ; Fermentation ; Fungi ; Mass Screening ; Population Characteristics ; Rhizopus ; Saccharomyces cerevisiae ; Sprains and Strains ; Wine

The internal transcribed spacer (ITS) regions including the 3'-end of 18S rRNA gene, 5.8S rRNA gene and the 5'-end of the 28S rRNA gene of Rhizopus spp. were amplified by PCR and analyzed by DNASIS program. Length polymorphism of these region ranged from 564 bp in R. oryzae to 789bp in R. stolonifer. The length and sequence of 5.8S was very conserved with 154~155 bp. The sequence of ITS2 was more variable than that of ITS1. The base substitution rates were ranged from 0 to 0.6069 per site, and higher rate was found in R. stolonifer. In general, transition was usually more frequent than transversion. On the basis of sequencing results, four groups were clustered with value of 61.9% similarity; R. oryzae, R. microspores, R. homothallicus, and R. stolonifer groups.
DNA, Ribosomal* ; Genes, rRNA ; Oryza ; Polymerase Chain Reaction ; Rhizopus* ; Sequence Analysis*

Repeated batch fermentation with Rhizopus arrhizus immobilized by polyurethane was optimized in details including the time to replace, the volume of the replaced medium and the optimal composition of the medium to replace. Immobilized cells showed stability for repeated use. Immobilized cells could be used for 9 batches, lasting 140h in flask and 6 batches in 5L fermenter when the substitute culture medium consisted of (%): soybean flour 3.0, earthnut oil 0.5 and the liquid was replaced by 40% . The time for fermentation was reduced largely and the lipase productivity was 3 - 6 times as high as that in batch fermentation.
Biotechnology ; methods ; Cells, Immobilized ; metabolism ; Fermentation ; Lipase ; biosynthesis ; Plant Oils ; Rhizopus ; enzymology ; Soybeans

Directed evolution strategy (error-prone PCR) was conducted to improve the activity of lipase from Rhizopus chinensis CCTCC M201021. Through two rounds of ep-PCR and pNPP top agar screening, two optimum mutant strains 1-11 and 2-28 were obtained with 2 and 4 fold of enzyme activity higher than that of parent strain, respectively. DNA sequencing of mutant lipase 2-28 revealed four amino acid substitutions: A129S, K161R, A230T, K322R. According to the simulated protein structure of Rhizopus chinensis lipase, A129S, K161R, A230T were located on the surface of the protein. A230T substitution improved the stability of the alpha-helix loop. K322R, near the catalytic center of lipase, located at a loop, formed a salt-bridge with a nearby aspartic acid (negative charged). Electrostatic force pulled the loop to the opposite direction of the substrate channel and made it easier for substrate to enter the lipase catalytic domain. Purified lipase was characterized and the result showed that Km of 2-28 lipase decreased by 10% compared with Km of the parent lipase, and Kcat was 2.75 fold improved than that of the original lipase.
Directed Molecular Evolution ; Lipase ; chemistry ; genetics ; Point Mutation ; Protein Engineering ; Rhizopus ; enzymology ; genetics

The effect of cultivation conditions on the optical purity of L(+)-lactic acid produced by Rhizopus oryzae HZS6 was investigated. The isomeric composition of lactic acid was influenced by the supplementation of L(+)-lactic acid to fermentation medium. L(+)-isomer increased with the dosage, no D(-)-lactic acid was observed when the concentration of supplemented L(+)-lactic acid in matrix was > or = 1.5 g/L. However, the L(+)-lactic acid yield, biomass and glucose conversion rate decreased with the dosage. With the same method, the supplementation of L(+)-lactic to substrate had no influence on isomeric composition of lactic acid by Lactobacillus and Escherichia coli.
Culture Media ; chemistry ; Fermentation ; Lactic Acid ; biosynthesis ; chemistry ; Rhizopus ; growth & development ; metabolism ; Stereoisomerism