• Journal of Fisheries and Marine Sciences Education
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• v.26 no.1
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• pp.1-9
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• 2014

One of freshwater rotifer (Brachionus calyciflorus) is very useful as a live food organism for early larval rearing of freshwater aquaculture industry. However, the knowledge about freshwater rotifer culture is scarce. On the other hand, marine rotifer culture as live food organisms is done, almost perfectly. In this study, I show to be benefit experimental results for successful freshwater larval rearing through the observation with microcosm structure in freshwater rotifer culture tanks.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.36 no.6
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• pp.606-613
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• 2003

This study investigated the effects of food type (condensed freshwater Chlorella, dried Chlorella, dried Spirulina, dried Schizochytrium, baker's yeast and $\omega-yeast$) and amount, and supplementation of vitamin $B_{12}$ on the growth of freshwater rotifer (Brachionus calyciflorus) in high density culture. Growth of rotifers fed condensed freshwater Chlorella was the highest and its density ranged $7.65-8.14{\times}10^3\;inds./mL.$ The primary lipid acids of rotifers fed condensed freshwater Chloyella were linoleic and linolenic, and their amount ($\%$ of total fatty acids) were $48.8\%\;and\;26.8\%,$ respectively. This suggests that condensed freshwater Chlorella would be an effective diet for high quality and quantity rotifers, which in turn serve as live food for freshwater fish larvae. Growth rate of rotifers with Chlorella supplementation increased as amount of supplementation increased up to 1.5 and 2.5 mg at 28 and $32^{\circ}C$, respectively. However, undissolved ammonia toxicity and packing volume of Chlorella in culture medium, reached the optimal conditions for the stable and effective cultivation of rotifers when amount of condensed freshwater Chlorella was 1.5 mg in dry weight per 1,000 rotifers at $28^{\circ}C\;and\;32^{\circ}C$ Growth of rotifers in condensed freshwater Chlorella with vitamin $B_{12}$ supplementation was significantly higher than that of rotifers without supplementation. However, no significant difference was found among the different concentrations of vitamin $B_{12}.$ Therefore, vitamin $B_{12}$ could improve the growth of rotifers (B. calyciflorus).

• Biomedical Science Letters
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• v.22 no.4
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• pp.150-159
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• 2016

Knowledge of the distribution and biodiversity of environmental bacteria and the ecosystem that influences them is crucial for predicting an ecosystem. However, bacterial culture methods can only analyze approximately 0.1% of the existing microorganisms, those that are readily cultured under laboratory conditions. By contrast, next-generation sequencing (NGS) has generally been known to obtain more diverse profiling of bacterial composition. We compared the bacterial communities using both a culture-dependent (MALDI-TOF) and culture-independent (NGS) methods. Environmental specimens were obtained from both freshwater and seawater. Water samples were also analyzed by both pyrosequencing and MiSeq sequencing, in order to select one NGS platform which could analyze comparatively more diverse microbiota. Bacterial distribution analyzed with MALDI-TOF showed no difference between the microbiota of freshwater and seawater, whereas the results analyzed with NGS distinguished between the two. The diversity indexes of MiSeq sequencing were higher than for Pyrosequencing. This indicated that MiSeq sequencing is capable of analyzing a comparatively wider diversity of bacteria. The genus of Flavobacterium and Planktophila were identified as being unique to freshwater, whereas EU801223 and OM43 were found in the seawater. Difference between the bacterial composition of the freshwater and seawater environments was identified by MiSeq sequencing analysis.

• Journal of Microbiology and Biotechnology
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• v.17 no.1
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• pp.168-175
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• 2007

We report here on the cultivation of numerous novel bacterial species from a eutrophic freshwater pond. A total of 60 strains, 15 strains per each culture medium, were obtained from the surface of a eutrophic freshwater pond by employing a conventional dilution-plating method with four different kinds of culture media, including R2A, 1/10R2A, PCA, and 1/10PCA. Among the 60 strains isolated, 27 strains showed less than 97% 16S rRNA gene sequence similarities to validly published species, and thus they are considered to comprise 19 novel species. Of the 27 strains assigned to the novel species, the majority of the strains (20 strains) were affiliated with the Alphaproteobacteria and Betaproteobacteria. The remaining 7 strains were affiliated with the Gammaproteobacteria, Firmicutes, Actinobacteria, and Deinococci. Because we have isolated 19 novel species from a usual freshwater pond using a conventional culturing technique, our results suggest that an unexplored ecosystem, even if it looks like a common ecosystem found elsewhere, harbors diverse unidentified microbes, which will be definitely further characterized.

• ALGAE
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• v.30 no.3
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• pp.207-216
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• 2015

Caloglossa species occurs in freshwater streams around Southest Asia. We report it from 2 different riverine sites in Kerala, India. Tetrasporangiate plants were observed in field collections from the Periyar River and Chalakkudy River. The Chalakkudy isolate did not reproduce in culture but the Periyar isolate developed abundant tetrasporangial sori in culture. Many spores were discharged and most were abortive, but some germinated normally, sporelings forming male gametophytes with numerous spermatangial sori and females with many procarps, viable carposporophytes and some nonfunctional (no carpospores) pseudocystocarps. Some carpospores germinated forming new tetrasporophytes. Molecular evidence (28S rDNA and rbcL) placed the Indian specimens close to C. beccarii and C. fluviatilis. Considering the freshwater habitat and morphology of vegetative thalli (blade shape, rhizoid arrangement, and number of rhizoid filament per cell), the Indian specimens should be assigned to C. beccarii.

• Journal of Aquaculture
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• v.1 no.2
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• pp.135-143
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• 1988

Rotifers became an important live food for fish larvae, especially for marine fishes, and Chlorella has been used as a very useful food for the mass culture of rotifer. However, not many tests for suitable Chorella species for the mass culture of rotifer were done and many of Chlorella sp. have been used without consideration of species for this purpose. There-fore, two species of marine Chlorella and four species of freshwater Chlorella were tested to select suitable species for the mass culture of a rotifer, Brachionus plicatilis. These Chlorella species were cultured in five different culture media; f/2, Erdschreiber, Complesal for marine species and S$\cdot$K, Wai and Complesal for freshwater species. Proximate analyses were done to see the protein, lipid and ash contents of a marine species, C. ellipsoidea and a freshwater species, C. vulgaris. Amino acids content of these species were also tested. C. ellipsoidea and C. vulgaris showed better growth than the other species. For marine Chlorella sp., f/2 media was better than Erdschreiber and Complesal. But for the freshwater species, Complesal showed the best result in growth. By the proximate analyses, C. ellipsoidea has higher lipid contents whereas C. vulgaris has higher protein and ash. In the analysis of amino acid of Chlorella, it was remarkable that freshwater Chlorella, C. vulgaris, has high content of $NH_3$ comparing with marine Chlorella, C, ellipsoidea. According to the above results, C. vulgaris seems have higher possibilities for mass culture of rotifer but further studies are needed.

• Journal of Aquaculture
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• v.18 no.2
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• pp.115-121
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• 2005

This study was performed to investigate the formation and mass production of resting eggs by freshwater rotifer, Brachionus calyciflorus as influenced by different aeration supplements and exchange intervals of culture water in 15-L culture vessels and 500 L culture tanks. The maximum densities and mixis rates of the rotifers were not different between experimental group exposed to air or oxygen supplements. However, the fertilization rate and formation of resting eggs of the rotifers in the air-supplemented group were significantly higher than those in the oxygen supplemented group. In the experiment concerning exchange interval of culture water, the maximum density of the rotifers and formation of resting eggs in the batch culture were significantly higher than those in the semi-continuous culture with exchange of water every day. The formation of resting eggs per Chlorella dry weight was highest in the semi-continuous culture with exchange of water every day. The resting eggs of rotifers were produced at a density of $51.8{\sim}57.9{\times}10^6$ eggs in 500-L culture tanks. In this study, the batch culture with air is an effective method for mass production of resting eggs by the freshwater rotifer, B. calyciflorus, and the efficiency of mass production of resting eggs by this rotifer was similar to that of the seawater rotifers, B. plicatilis and B. rotundiformis.

• Korean Journal of Veterinary Service
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• v.16 no.2
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• pp.111-119
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• 1993

In this study, we carried out the rapid diagnostic system based on indirect fluorescent anti-body technique (IFAT) for detection of bacterial diseases in cultured freshwater fishes. 1. When the fishes were tested with graded dilution of Edwardsiella tarda FPC 470 bacteria detection from ten fishes Injected with $4.1{\times}10^3$colony forming unit(CFU) /ml, all of them were detected by IFAT but only two fishes were recognizable by the culture method in the tested fishes injected with $4.1{\times}10^3$CFU /ml. 2. The bacteria E. tarda could be detected by IFAT method from 1 to 48hrs after Injection in the tissues tested such as kidney, liver and spleen of the fishes, whereas detection by culture method could be recognized from 1 to 48hrs after injection In the kidney and spleen but it was not possible from preinjection to 1 hr in the liver. 3. Thus, IFAT proved to be more useful technique than plate culture method in the diagnosis of Edwardsiellosis in the freshwater fishes.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.33 no.2
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• pp.93-97
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• 2000

This study was carried out to investigate the effect of rotifer fed the different diets in high density culture on larval flounder Paralichthys olivaceus. Potifer was enriched with enrichment supplements, Marine ${\alpha}\;and\;{\omega}-yeast$ for 6 hours after being cultured with freshwater Chlorella for 18 hours during high density culture before it was fed to larval flounder. And rotifer was culutured with marine Chlorella and freshwater Chlorella for 24 hours during semi-continuous high density culture before it was fed to larval flounder. Culture tanks(21 working volum) set for rotifer culture in a water bath($28{\circ}C$) were continuously supplied with oxygen gas. The content of n-3 HUFA to fatty acids in rotifer(dry weight ${\%}$) enriched with Marine ${\alpha}$ for 6 hours and cultures with marine Chlorella for 24 hours were higher than that in rotifer enriched with ${\omega}-yeast$ for 6 hours or cultured with freshwater Chlorella for 24 hours. The growth and survival rates of larval flounder fed on rotifer enriched with Marine ${\alpha}$ for 6 hours and cultured with marine Chlorella for 24 hours were higher than those of larval flounder fed on rotifer enriched with ${\omega}-yeast$ for 6 hours or cultured with freshwater Chlorella for 24 hours. And the content of n-3 HUFA of larval flounder fed on rotifer enriched with Marine ${\alpha}$ for 6 hours was higher than that of larval flounder fed on other rotifers, The results from this study indicated that rotifer culture with marine Chiorelia would be suitable for the high density culture and effective diet for the growth of larval flounder.

• Korean Journal of Organic Agriculture
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• v.22 no.4
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• pp.743-760
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• 2014

This study aimed to isolate and identify freshwater algae from the organic agricultural ecosystems and investigate its biological characteristics to study the possibility of utilizing a biomass freshwater algae in organic farming. In the survey area, average water temperature was $12.4{\sim}28.2^{\circ}C$ and the pH ranges were from 6.1 to 8.5. The solid culture method is more suitable than liquid culture method for isolation of freshwater algae with lower contamination level and higher isolation frequency. A total of 115 strains were isolated from six freshwater algae habitats in nine regions in Korea. BGMM (BG11 Modified Medium) amended with NaNO3 and $KNO_3$ as a nitrogen, and $Na_2CO_3$ as carbon source was designed to isolate and culture freshwater algae. Absorbance of freshwater algae culture has increased dramatically to four days and decreased after eight days after inoculation. CHK008 of the seven isolates showed the highest absorbance in seven days after culturing in BGMM. The optimal pH of BGMM for culturing freshwater algae was pH 6-7. As light intensity increased, growth of freshwater algae increased. Among the five kinds of carbon sources, glucose and galactose promoted good growth of freshwater algae in BGMM. The colony color of purified 16 green algae isolates showed a separation of green, dark and light green, and of them, eleven algae strains showed a strong fluorescent light under fluorescence microscopy. Cell size of the green algae showed a wide range of variation depending on the species. General morphology of the green algae strains was spherical. Chlamydomonas sp. was elliptical, and Chlorella sorokiniana was ellipsoidal and cylindrical. All strains of the green algae except for Chlamydomonas sp. did not have flagella. One isolate of Chlamydomonas sp. and five isolates of C. sorokiniana secreted mucus. Sixteen isolates of 16 green algae were identified as two family and six species, Chlorella vulgalis, C. sorokiniana, C. pyrenoidosa, C. kessleri, C. emersonii, and Chlamydomonas sp. based on their morphological characteristics.