• ALGAE
• /
• v.17 no.3
• /
• pp.153-159
• /
• 2002

Partial 16S rRNA gene sequences of seven cyanophycean strains from the National Instiute of Environmental Research of Korea - Microcystis aeruginosa, M. aeruginosa f. aeruginosa, M. ichthyoblade, M. viridis, Anabaena flos-aquae, and Oscillatoria sancta - were analyzed and the phylogenetic relationship of Microcystis among Cyanophyceae were evaluated. Based on sequence analysis results, Microcystis is monophyletic, the clade of which supported 100% bootstrap tress, and distinguished clearly from the other taxa. Therefore, the partial 16S rRNA gene sequences can be a useful and efficient tool for distinguishing Microcystis from other cyanophycean without axenic culture or cloning.

• Journal of Marine Bioscience and Biotechnology
• /
• v.2 no.2
• /
• pp.77-80
• /
• 2007

Macroalgal tissues can be used as indicating materials for environmental assessment using several algal biotechnology techniques. As bioassay test organisms, macroalgal tissues are required as an axenic state for suitable biological indicators. Callus formation and blade regeneration under suitable culture conditions are also useful for the tests. Quantitative method using tetrazolium chloride or $alamarBlue^{TM}$ is devised on a rapid assessment of the seaweed viability. The use of RT-PCR especially differential display technique should provide the means for the detection and isolation of the responding genes induced by the environmental stress. Seaweed thriving in more environmental changes might contain more diverse biologically active substances.

• Mycobiology
• /
• v.32 no.4
• /
• pp.197-198
• /
• 2004

A new technique for single spore isolation was developed for predacious fungi forming constricting rings directly on the spores using Dactylaria brochopaga and Arthrobotrys dactyloides. Constricting rings were induced directly on the spores by transferring the spores in 25 ppm solution of DL-Valine in sterile distilled water. Freshly hatched and thoroughly washed second stage juveniles of Meloidogyne incognita were transferred into cavity blocks containing induced rings for trapping and killing of nematodes. The killed nematodes were surface sterilized with streptomycin and inoculated into petri dishes containing maize meal agar media with 100 ppm streptomycin. The petri dishes were incubated at $29{\pm}1^{\circ}C$ for few days which yielded axenic culture of these fungi.

• Journal of Animal Science and Technology
• /
• v.65 no.2
• /
• pp.387-400
• /
• 2023

Ruminal protozoa, especially entodiniomorphs, engulf other members of the rumen microbiome in large numbers; and they release oligopeptides and amino acids, which can be fermented to ammonia and volatile fatty acids (VFAs) by amino acid-fermenting bacteria (AAFB). Studies using defaunated (protozoa-free) sheep have demonstrated that ruminal protozoa considerably increase intraruminal nitrogen recycling but decrease nitrogen utilization efficiency in ruminants. However, direct interactions between ruminal protozoa and AAFB have not been demonstrated because of their inability to establish axenic cultures of any ruminal protozoan. Thus, this study was performed to evaluate the interaction between Entodinium caudatum, which is the most predominant rumen ciliate species, and an AAFB consortium in terms of feed degradation and ammonia production along with the microbial population shift of select bacterial species (Prevotella ruminicola, Clostridium aminophilum, and Peptostreptococcus anaerobius). From an Ent. caudatum culture that had been maintained by daily feeding and transfers every 3 or 4 days, the bacteria and methanogens loosely associated with Ent. caudatum cells were removed by filtration and washing. An AAFB consortium was established by repeated transfers and enrichment with casamino acids as the sole substrate. The cultures of Ent. caudatum alone (Ec) and AAFB alone (AAFB) and the co-culture of Ent. caudatum and AAFB (Ec + AAFB) were set up in three replicates and incubated at 39℃ for 72 h. The digestibility of dry matter (DM) and fiber (NDF), VFA profiles, ammonia concentrations, pH, and microscopic counts of Ent. caudatum were compared among the three cultures. The co-culture of AAFB and Ent. caudatum enhanced DM degradation, VFA production, and Ent. caudatum cell counts; conversely, it decreased acetate: propionate ratio although the total bacterial abundance was similar between Ec and the Ec + AAFB co-culture after 24 h incubation. The ammonia production and relative abundance of C. aminophilum and P. anaerobius did not differ between AAFB alone and the Ec + AAFB co-culture. Our results indicate that Ent. caudatum and AAFB could have a mutualistic interaction that benefited each other, but their interactions were complex and might not increase ammoniagenesis. Further research should examine how such interactions affect the population dynamics of AAFB.

• ALGAE
• /
• v.24 no.3
• /
• pp.163-168
• /
• 2009

Grateloupia filicina (J.V. Lamouroux) C. Agardh (Halymeniaceae, Cryptonemiales, Rhodophyta) is an edible seaweed as well as an important source of carrageenan. In the present study, attempt has been made to develop a suitable protocol for effective regeneration of the seaweed and the rapid multiplication of the desired varieties. The young upright thallus of G. filicina was grown in axenic culture using both solid and liquid media. The various media tested were f/2, Provasoli’s Enriched Seawater (PES) and Enriched Seawater (ESW). The effect of glycerol (as a carbon source) and various plant growth regulators i.e. auxin (NAA) and cytokinins (Kinetin and BA) were tested. Although, regeneration of young thalli was observed from the cut ends in all the media, better growth was found in f/2, PES, f/2 (0.5% Glycerol), f/2 (NAA ${10^{-5}}_M)\;and\;f/2\;(BA\;{10^{-6}}_M$). On the other hand callusing was observed only in solid media supplemented with low concentration of Glycerol (0.5%) in f/2, NAA ${10^{-5}}_M\;in\;f/2,\;PES\;and\;BA\;{10^{-5}}_M$ in f/2. Young thalli were developed from the callus sub culture after 40 days of inoculation.

• Korean Journal of Soil Science and Fertilizer
• /
• v.20 no.3
• /
• pp.269-274
• /
• 1987

A laboratory experiment was conducted to find out the effect of inoculation with plant growth of associative $N_2$-fixing bacteria on the combination of eight different rice seedling with seven different associative $N_2$-fixing bacteria in which were isolated and identified from grasses and rice in saline and reclaimed saline paddy soil. Those were examined in N-free axenic culture medium. The result of this experiment exemplified the contribution of associative $N_2$-fixing bacteria to their host plant were varied much by the combination of rice cultivars and bacterial strains. Acetylene reduction ($N_2$-fixation) activity seems to be more variable with respect to the combination of rice cultivars and bacterial strains. The relationship between acetylene reduction activity and rice performance such as dry matter weight, plant height, root length, and number of root were statistically insignificant. However, in comparision with the control, the dry matter yield of Annapuruna was increased by inoculation of all the seven bacteria strains. Among the seven rice cultivars, the average acetylene reducing activity was the highest in Annapuruna, and Shingwang, and the lowest in IR-8 inoculated with Pseudomonas sp H8. Among the seven bacterial strains the highest acetylene reducing activity was obtained by the combination of Shingwang with Pseudomonas sp H8.

• Journal of Aquaculture
• /
• v.2 no.1
• /
• pp.1-7
• /
• 1989

Axenic tissue culture of a marine red algae Porphyra yezoensis foma narawaensis was established for the vegetative propagation of tissues as a seed stock and for the development of a low salinity-tolerant cell line. Callus tissues have been induced from the vegetative area of blade away from the hold fast when grown on PES-agar medium. The brownish red fragile callus was maintained under fluorescent light of ca. 2000 lux with 12 : 12 hr L : D at $16^{\circ}C$. Amounts of carbohydrate and protein was determined against the weight of callus. Optimum temperature of the callus growth was $14^{\circ}C\~18^{\circ}C$. Optimun concentration of sodium chloride was $2.0\%$ for the callus growth in PES-agar medium.

• Journal of Microbiology and Biotechnology
• /
• v.10 no.3
• /
• pp.429-433
• /
• 2000

Giardia lamblia, a human pathogen causing outbreaks of diarrhea, recently became a focus of great concerns in the fields of both medical and environmental microbioloty. To develop the experimental tools to study giardiasis, encystation, one of the major processes in its life cycle, was reconstituted by inducing an axenic culture of a flagellated form of G. lamblia into a cyst from under high concentration of bile and alkaline pH condition. The successful induction was confirmed by Northern analysis of resulting increased expression of the CWPl gene encoding the cyst wall protein 1. An examination of the encystation process with SEM (scanning electron microscopy) and TEM (transmission electron microscopy) revealed that the trophozoite, a flagellate with a bilateral symmetry, was transformed to a cyst form with an oval-shape and defined filamentous wall. The encystation was found to cause a disappearance of the flagella and an invagination of the adhesive disc. An extensive formation of rER (rough endoplasmic reticulum) was observed after 24h of induction, indication an active synthesis and export of proteins during this process. The vital staining of the invitro-induced systs showed that most cysts maintained their viability.

• Parasites, Hosts and Diseases
• /
• v.55 no.1
• /
• pp.81-84
• /
• 2017

Trypanosoma cruzi is the etiological agent of Chagas disease. Epimastigote forms of T. cruzi can be readily cultured in axenic conditions. Ethanol and dimethyl sulfoxide (DMSO) are commonly used solvents employed as vehicles for hydrophobic compounds. In order to produce a reference plot of solvent dependent growth inhibition for T. cruzi research, the growth of epimastigotes was analyzed in the presence of different concentrations of ethanol (0.1-4.0%) and DMSO (0.5-7.5%). The ability of the parasites to resume growth after removal of these solvents was also examined. As expected, both ethanol and DMSO produced a dose-dependent inhibition of cellular growth. Parasites could recover normal growth after 9 days in up to 2% ethanol or 5% DMSO. Since DMSO was better tolerated than ethanol, it is thus recommended to prefer DMSO over ethanol in the case of a similar solubility of a given compound.

• The Plant Pathology Journal
• /
• v.19 no.3
• /
• pp.152-158
• /
• 2003

Stromata of the white root rot fungus, Rosellinia necatrix, were produced on diseased roots although they were reported to develop rarely in nature. Forty-two (42) out of 47 samples produced synnemata while 23 developed stromata. Forty-seven (47) isolates obtained from diseased root samples were divided into 24 mycelium compatibility groups (MCGs). Sixteen (16) out of 24 MCGs produced stromata. Single ascospore isolates from 10 stroma samples produced dsRNA-containing isolates from diseased tissue beneath stromata. The frequency of synnema production on axenic culture varied among isolates with different origin. The dsRNA was not transmitted vertically to the ascospore offspring despite the infection of various dsRNA in the parental isolates. The dsRNA was absent in 35 ascospore isolates in two stroma samples that originated from the isolates, in which dsRNA was not eliminated by hyphal tip isolation. Consequently, sexual reproduction in the white root rot fungus was suggested to produce propagules as a new infection source and to have the function to eliminate infectious factors such as mycoviruses.