Oryzae Spores Research Articles

The influence of inoculum composition on selected bioactive and nutritional parameters of grass pea tempeh obtained by mixed-culture fermentation with Rhizopus oligosporus and Aspergillus oryzae strains

Tempeh is a popular Indonesian product obtained from legume seeds by solid-state fermentation with Rhizopus sp. The aim of this research was to study the effect of simultaneous mixed-culture fermentation of grass pea seeds on selected parameters of products as compared to traditional tempeh. The inoculum contained different ratios of Rhizopus oligosporus and Aspergillus oryzae spores. The simultaneous fermentation of grass pea seeds with inoculum consisting of 1.2 × 10(6) R. oligosporus and 0.6 × 10(6) A. oryzae spores (per 60 g of seeds) resulted in a product of improved quality, as compared with traditionally made tempeh (obtained after inoculation with 1.2 × 10(6) R. oligosporus spores), at the same fermentation time. This product had radical scavenging ability 70% higher than the one obtained with pure R. oligosporus culture and contained 2.23 g/kg dm of soluble phenols. The thiamin and riboflavin levels were above three (340 µg/g dm) and two (50.50 µg/g dm) folds higher than in traditionally made tempeh, respectively. The product had 65% in vitro bioavailability of proteins and 33% in vitro bioavailability of sugars. It also contained 40% less 3-N-oxalyl-L-2, 3-diaminopropionic acid (0.074 g/kg dm), as compared to traditional tempeh.

Immobilization of Aspergillus oryzae with κ-carrageenan for soybean oligosaccharide hydrolysis

The immobilized Aspergillus oryzae spores in κ-carrageenan were used for production of α-galactosidase. The immobilized cells could be used up to 5 repeated cycles for enzyme production. They were employed for raffinose family oligosaccharides (RFO) hydrolysis in batch, repeated batch, and continuous operations after 5 days of fermentation. In batch mode, 65, 73, and 80% of RFOs were hydrolyzed after 3, 6, and 12 h, respectively; in repeated batch; 70, 63, 52, and 45% were hydrolyzed in 1, 2, 3, and 4 repeated cycles. In the fluidized bed reactor, 65, 58, 53, 48, and 44% RFOs were hydrolyzed at flow rates of 25, 50, 75, 100, and 125 mL/h respectively. The κ-carrageenan beads maintain good mechanical strength up to 4 repeated uses for RFO hydrolysis in soymilk, and their use in the hydrolysis of RFOs of soybean is a promising solution to overcome flatulence and to increase consumption of soy products.

Radiobiological investigations of soft X-rays near carbon, nitrogen, oxygen K-shell edges on Aspergillus oryzae spores

Soft X-rays at carbon, nitrogen, oxygen K-shell edges have special radiobiological effects. Using Aspergillus oryzae spores as sample, the radiation effects of soft X-rays near the K-shell edges of C, N and O elements from synchrotron radiation were investigated. Also the dose depositions of different X-ray energies in spore were discussed. At the same time, the spores were irradiated by gamma rays from 60Co and relative biological effects were compared with those produced by soft X-rays. The results showed that soft X-rays near K-shell edges of O element had higher ability of radiation damage than that of X-rays near K-shell edges of C and N elements as compared with one another. But they all had higher killing abilities per unit dose than that of gamma rays from 60Co. The relative biological effects (RBEs), the comparison of dose to gamma rays at 10% survival level, of the three soft X-rays were 1.65, 1.73 and 1.91, respectively.

A potato carboxypeptidase inhibitor gene provides pathogen resistance in transgenic rice

A defensive role against insect attack has been traditionally attributed to plant protease inhibitors. Here, evidence is described of the potential of a plant protease inhibitor, the potato carboxypeptidase inhibitor (PCI), to provide resistance to fungal pathogens when expressed in rice as a heterologous protein. It is shown that rice plants constitutively expressing the pci gene exhibit resistance against the economically important pathogens Magnaporthe oryzae and Fusarium verticillioides. A M. oryzae carboxypeptidase was purified by affinity chromatography and further characterized by mass spectrometry. This fungal carboxypeptidase was found to be a novel carboxypeptidase B which was fully inhibited by PCI. Overall, the results indicate that PCI exerts its antifungal activity through the inhibition of this particular fungal carboxypeptidase B. Although pci confers protection against fungal pathogens in transgenic rice, a significant cost in insect resistance is observed. Thus, the weight gain of larvae of the specialist insect Chilo suppressalis (striped stem borer) and the polyphagous insect Spodoptera littoralis (Egyptian cotton worm) fed on pci rice is significantly larger than that of insects fed on wild-type plants. Homology-based modelling revealed structural similarities between the predicted structure of the M. oryzae carboxypeptidase B and the crystal structure of insect carboxypeptidases, indicating that PCI may function not only as an inhibitor of fungal carboxypeptidases, but also as an inhibitor of insect carboxypeptidases. The potential impact of the pci gene in terms of protection against fungal and insect diseases is discussed.

Surface properties of Aspergillus oryzae spores investigated by atomic force microscopy

Spores of the filamentous fungus Aspergillus oryzae have a great biotechnological potential for the production of highly active proteins. To date, little is known about the molecular mechanisms of spore aggregation, a phenomenon observed during germination in liquid medium. Here, atomic force microscopy (AFM) imaging and force measurements were used to characterize, under aqueous conditions, the surface morphology and macromolecular interactions of A. oryzae spores in relation to their aggregation behavior. Dormant spores were covered with a discontinuous layer of about 35 nm thickness, as revealed by height images. High-resolution deflection images showed that this layer consisted of rodlets, 10±1 nm in diameter, that were assembled in parallel to form fascicles interlaced with different orientations. The germinating spore surface was much rougher and showed streaks oriented in the scanning direction, indicating that the probe was interacting with soft material. Retraction force curves were strikingly different depending on the spore physiological state: while dormant spores exhibited non-adhesive properties, germinating spores showed single or multiple attractive forces of 400±100 pN magnitude, along with characteristic elongation forces and rupture lengths ranging from 20 to 500 nm. These elongation forces are attributed to the stretching of long, flexible cell surface macromolecules and suggested to play a role in the aggregation process by promoting bridging interactions.

青ヶ島の芋焼酎製造用粉状麹の主要糸状菌の由来源粉状麹に関する研究 (第2報)

Kona-koji was prepared without the addition of a koji starter (Tanc-koji) for the production of Imo-shochu. The spores of molds carried in the air affected growth during the preparation of koji. So, we isolated the spores of molds from the vicinity of the places used for the preparation of koji and production of shochu.As shown by the results, a 103 order of colonies per gram·koji of A. oryzae were isolated from kojimuro solids, shochu distillery solids and from the leaves of N. antiqua that are used to wrap the koji A. oryzae spores were also isolated from the air of the koji-muro and shochu distillery. In addition spores of A. niger and other molds were also isolated.We measured the enzyme activity of these strains and investigated their physiological characteristics. Their acidity was higher than that of the standard strains. The characteristics of these strains agreed with those of strains isolated from kona-koji. Therefore, we found that spores of Aspergillus sp. were mixed with the raw material for koji from the leaves of N. antiqua or airborne spores, and these spores grew during the preparation of koji.Further more, spores of other mold contaminating koji were isolated from the leaves of N. antiqua, but they were not detected in the koji. We found that their mold were selected against as the temperature of koji rose to 40C during its preparation.

A case of occupational allergic bronchopulmonary aspergillosis unique to Japan

A 15-year-old female was diagnosed in 1980 as having allergic bronchopulmonary aspergillosis (ABPA) due to Aspergillus fumigatus based on Rosenberg and Patterson's criteria for the disease. The patient is the eldest daughter of a family of domestic brewers of soy sauce and bean paste in a small village, an occupation unique to Japan. The brewing process involved the use of Aspergillus oryzae as a fermenting agent. The patient had experienced episodic wheezing and pulmonary infiltrates during the same seasons in the previous three years, corresponding to the time of the highest A oryzae spore concentrations in the living area, suggesting high exposure to the Aspergillus spores in the aetiology of her exacerbations. She had a prominent family history of atopy and was demonstrated to be sensitive to a variety of aeroallergens in addition to A fumigatus. She was treated effectively by bronchial toiletting via broncho-fibrescope and theophylline medication until April 1981, when she moved to another city. During her life there, chest X-rays repeatedly showed abnormal shadows, and she was treated with inhalations of amphotericin B and bronchial toiletting several times at a hospital. She returned to her home town after seven years in April 1988 and visited the hospital to check her condition. Although she had been away from heavy exposure to A oryzae spores for seven years, precipitins to the culture medium of A oryzae were demonstrated to be far more prominent than those to A fumigatus antigen. Although her family had been exposed to A oryzae spores continuously, the patient was the only family member with ABPA due to A fumigatus and possibly due to A oryzae.(ABSTRACT TRUNCATED AT 250 WORDS)

Neutrophil chemotactic responses induced by fresh and swollen Rhizopus oryzae spores and Aspergillus fumigatus conidia.

With the induction of germination, Rhizopus oryzae spores and Aspergillus fumigatus conidia activate the complement system and induce neutrophil chemotaxis. In contrast, freshly isolated R. oryzae spores did not induce neutrophil migration into lung tissue of mice after intranasal inoculation. Moreover, in microchemotaxis assays neither fresh R. oryzae spores nor A. fumigatus conidia activated sera to stimulate human neutrophil chemotaxis above control migration until at least 10(7) or 10(8) spores or conidia per ml of sera were used. The increased generation of chemotactic factors by swollen spores and conidia was not due to an increased surface area, as there was decreased neutrophil chemotactic response to Rhizopus or Aspergillus hyphae when compared with swollen spores or conidia.