• Mycobiology
• /
• v.39 no.2
• /
• pp.79-84
• /
• 2011

Nuclear distribution within the extra-radical fungal structures and during spore production in the arbuscular mycorrhizae fungus Glomus intraradices was examined using an in vitro monoxenic culture system. A di-compartmental monoxenic culture system was modified using a nitrocellulose membrane and a coverglass slip for detailed observations. Nuclear distribution was observed using the fluorescent DNA binding probes SYBR Green I and DAPI. Both septate and non-septate mycelial regions were observed, but cytoplasmic contents were only found within non-septate mycelia. Nuclear fluorescent staining revealed that the non-septate hyphal region contained nuclei only with cytoplasm, and that nuclear distribution was limited by septa. Swollen hyphal bodies were often associated with septate and empty-looking hyphae. Cytoplasmic contents filled the swollen hyphal body from the non-septate hyphal region following removal of the septa. As a consequence, the swollen body developed into a new spore. These observations provide understanding about the distribution of AM fungal nuclei within extra-radical mycelia and during spore formation. The results suggest a mechanism by which the development of a cytoplasm-containing mycelium is controlled by the formation or removal of septa to efficiently maintain and proliferate essential contents. This mechanism may provide a survival strategy to the fungus.

• Journal of Microbiology and Biotechnology
• /
• v.11 no.1
• /
• pp.72-78
• /
• 2001

It is possible ot prepare protoplasts of the zygomycete fungus, Phycomyces blakesleeanus, by digesting the cell wall of spore germlings with commercially available chitinase and chitosanase. However, the cells without any cell walls immediately form large aggregates, and thus, it is difficult to isolate the individually separated protoplasts. Inherent problem with the formation of aggregates in preparing protoplasts could be solved by the use of bovine serum albumin (BSA). As a result, we were able to prepare a large number of single protoplsts quickly and easily. We took time-lapse photomicrographs of the formation of protoplasts, and found that there were certain regions of the cell wall of spore germlings that were sensitive to chitinase and chitosanase, although the cell wall of the original spores is known to be insensitive to these enzymes. There are two kinds of cell walls on a spore germling; one with a bound wheat germ agglutinin (WGA), and the other a bound concanavalin A (ConA). Furthermore, only cells with walls which had bound WGA were able to regenerate, while those with walls with bound ConA were not able to regenerate.

• Journal of Microbiology and Biotechnology
• /
• v.18 no.5
• /
• pp.913-917
• /
• 2008

The cyclic undecapeptide, cyclosporin A (CyA), is one of the most commonly prescribed immunosuppressive drugs. It is generated nonribosomally from a multifunctional cyclosporin synthetase enzyme complex by the filamentous fungus Tolypocladium niveum. In order to maximize the production of CyA by wild-type T. niveum (ATCC 34921), each of three culture stages (sporulation culture, growth culture, and production culture) were sequentially optimized. Among the three potential sporulation media, the SSMA medium generated the highest numbers of T. niveum spores. The SSM and SM media were then selected as the optimal growth and production culture media, respectively. The addition of valine and fructose to the SM production medium was also determined to be crucial for CyA biosynthesis. In this optimized three-stage culture system, 3% of the spore inoculum generated the highest level of CyA productivity in a 15-day T. niveum production culture, thereby implying that the determination of an appropriate size of T. niveum spore inoculum plays a critical role in the maximization of CyA production.

• Korean Journal of Soil Science and Fertilizer
• /
• v.45 no.4
• /
• pp.582-592
• /
• 2012

Microorganisms present in the rhizosphere soil plays a vital role in improving the plant growth and soil fertility. Many kinds of fertilizers including chemical and organic has been approached to improve the productivity. Though some of them showed significant improvement in yield, they failed to maintain the soil properties. Rather they negatively affected soil eventually, the land became unsuitable for agricultural. To overcome these problems, microorganisms have been used as effective alternative. For past few decades, plant growth promoting rhizobacteria (PGPR) and arbuscular mycorrhizal fungi (AMF) have been used as effective inoculants to enhance the plant growth and productivity. PGPR improves the plant growth and helps the plant to withstand biotic and abiotic stresses. AM fungi are known to colonize roots of plants and they increase the plant nutrient uptake. Spore associated bacteria (SAB) are attached to spore wall or hyphae and known to increase the AMF germination and root colonization but their mechanism of interaction is poorly known. Better understanding the interactions among AMF, SAB and PGPR are necessary to enhance the quality of inoculants as a biofertilizers. In this paper, current knowledge about the interactions between fungi and bacteria are reviewed and discussed about AMF spore associated bacteria.

• Korean Journal of Food Science and Technology
• /
• v.10 no.2
• /
• pp.224-230
• /
• 1978

Heat resistant putrefactive microorganisms causing spoilage of canned and processed foods were surveyed in the compost on mushroom growing bed, casing soil, raw mushrooms and canned products before sterilization at canneries located at 8 places including Buyo in Chung-Cheung-Do and monitored the total count and spore formers from the sample taken. The 9 strains of most severe heat resistant among the selected 140 spore formers were selected and determined D and Z value by TDT method. The most strong heat resistant strain was No. F-10, facultative thermophile, which was isolated from raw mushroom in Buyo area and it's Z value was $21.1^{\circ}F$ (M/15 phosphate buffer solution) and $D^{250}$ was 6.6 min.

• Korean Journal of Microbiology
• /
• v.15 no.3
• /
• pp.103-112
• /
• 1977

Several strains of spore-forming lacticacid bacteria were isolated from natural sources such as soils, cereals, and foods. The general morphological and physiological characteristics of the strain 6-4 were investigated nad compared with some other industrial strains. The effects of fructose-1,6-diphoshpate (FDP), adenosine triphosphate (ATP), and pH on the lactate dehydrogenase(LDH) activity of the strain were studied, and the changes in LDH activity and spore formation under various cultural conditions were researched. The results were as follows. 1. This strain was identified to Bacillus coagulans Hammer and distributed widely in natural sources. 2. The strain strongly converted various fermentation substrates in to L(+)-lacticacid in anaerobic conditioins, and many spores that were of great advantages to the industrial application were formed easily in the aerobic condition. 3. The LDH activity of this strain was activated by FDP and inhibited by ATP. The optimal pH for the enzyme activity was 6.0-6.5. 4. In the anaerobic culture condifion, the large amount of glucose added in the medium increased the LDH activity, but the cells were not committed to sporulate. 5. When none or a very small amount of glucose (less than 0.5%) was added to culture medium in the aerobic condition, the LDH activity was decreased and many spore were produced with final pH higher than 8.5. 6. The additioin of large amount of glucose (more than 2.0%) in aerobic culture increased the LDH activity and inhibited strongly the spore formation with final pH lower than 6.0.

• Research in Plant Disease
• /
• v.8 no.2
• /
• pp.124-130
• /
• 2002

In 1998, a pathogen isolated from infected onions was identified as Aspergillus niger. At 3$0^{\circ}C$, A. niger AnYD-1 showed the best mycelial growth, spore germination, and high pathogenicity to onions. In spite of the weak inhibitory effect of flusilazole and hexaconazole on the mycelial growth on PDA, they showed the specific inhibitory activity against the formation of spores in the vapour phase. With flusilazole and hexaconazole, the effects of the solvent, the applied concentration and the incubating temperature on the activities inhibiting the spore formation were confirmed. Their inhibitory effect on the spore formation in vapour phase was excellent by solving them with dimethylsulfoxide and dimethylformamide among tested solvents, and applying them at high temperature such as 30~35$^{\circ}C$.

• Journal of Plant Biology
• /
• v.37 no.1
• /
• pp.43-51
• /
• 1994

Spore morphology of 14 species of Ophioglossaceae is examined, and descriptions and key based on spore morphology are provided. In addition, spores of one species of Angiopteris and three species of Osmunda are examined for comparision with those of Ophioglossaceae. Spore shape at proximal face is sub triangular or triquete in Botrychium and circular in Ophiog~ lossum, Angiopteris and Osmunda. Based on the wall sculpturing patterns, three groups can be recognized within Botrychium, and the differences of wall sculpturing among these groups are smaller as compared to those among Botrychium, Ophioglossum, Osmunda and Angiopteris. This result supports the previous infrafamilial system of Clausen, which was mainly based on the characteristics of vernation, habit, fertile and sterile segments of the leaf, and gametophyte. Spores of nine species of Ophioglossum, which are circular in proximal face and fossulate or foveolate in wall sculpturing, are quite uniform as compared to those of Botrychium. Therefore they should be kept under a single genus rather than split into four genera suggested by Nishida (1952).(1952).

• The Korean Journal of Mycology
• /
• v.12 no.4
• /
• pp.141-152
• /
• 1984

Aspergillus niger van Tieghem was cultured by the method of synchronous and submerged culture. Throughout the culture, sporulation was occured. Highly phosphorylated nucleotides in sporulating mycelia were detected to assure whether the eucaryotic Aspergillus niger produce these substances or not during the differentiation. Phosphorylated nucleotides were extracted from the conidiophore, bearing mycelia and spore forming body, these nucleotides were identified by TLC with P.E.I. cellulose. Guanosine tetraphosphate was found in both phialide forming mycelia and spore forming body. The contents of free amino acids were assayed and its level was found to increase at early stage of sporulation. The effects of 8-azaguanine examined, it was found to prevent spore formation and to made abnormal structure. The effects of inosinic monophosphate and guanosine monophosphate on spore formation were examined, spore formation was enhanced by these nucleotides.

• Journal of Microbiology and Biotechnology
• /
• v.23 no.1
• /
• pp.15-21
• /
• 2013

We previously observed that Bacillus subtilis spores from sspE mutants presented a lower germination capacity in media containing high salt concentrations (0.9M NaCl). This deficiency was attributed to the absence of SASP-E (gamma-type small-acid-soluble protein), rich in osmocompatible amino acids released by degradation. Herein we observed that, in addition, this mutant spore presented a reduced capacity to use L-alanine as germinant (L-ala pathway), required longer times to germinate in calcium dipicolinate ($Ca^{2+}$-DPA), but germinated well in asparagine, glucose, fructose, and potassium chloride (AGFK pathway). Moreover, mild sonic treatment of mutant spores partially recovered their germination capacity in L-ala. Spore qualities were also altered, since sporulating colonies from the sspE mutant showed a pale brownish color, a higher adherence to agar plates, and lower autofluorescence, properties related to their spore coat content. Furthermore, biochemical analysis showed a reduced partition in hexadecane and a higher content of $Ca^{2+}$-DPA when compared with its isogenic wild-type control. Coat protein preparations showed a different electrophoretic pattern, in particular when detected with antibodies against CotG and CotE. The complementation with a wild-type sspE gene in a plasmid allowed for recovering the wild-type coat phenotype. This is the first report of a direct involvement of SASP-E in the spore coat assembly during the differentiation program of sporulation.