Optimizing culture conditions for the antagonistic activities of Trichoderma viride against Sclerotium rolfsii causative agent of southern blight disease of tomato

Aims: Sclerotium rolfsii is a pathogen of agricultural crops such as tomatoes. Trichoderma viride has been shown to control this pathogen effectively but the optimum conditions of this biocontrol agent need to be determined. This piece of research was therefore aimed at studying the conditions that could be maintained in maximizing the full potential of T. viride. Methodology and results: Malt extract agar was separately supplemented with different carbon sources (glucose, sucrose, maltose, lactose, and mannitol), nitrogen sources (peptone, ammonium nitrate, zinc nitrate and sodium nitrate) as well as salts (NaCl, CaCl2, KI, BaCl2) at different concentrations. Effect of different temperature and pH ranges was also evaluated. All the carbon used supported the growth of both S. rolfsii and T. viride at all concentrations. The growth of S. rolfsii was less than 90 mm at 3% of all the carbon used compared to the plates in which no carbon sources were added whereas the growth of T. viride was 90 mm. There were morphological changes in the growth of both T. viride and S. rolfsii with increase in concentrations of peptone and ammonium nitrate. The greenish colour of T. viride was completely lost while S. rolfsii became fluffier. For peptone, the percentage reduction ranged from 68.52 to 63.33 while for zinc nitrate and sodium nitrate, the percentage reduction ranged from 85.19 to 80.74 and 55.00 to 43.70 respectively. Also, there was increase in antagonistic property of T. viride with the inclusion of salts (NaCl, CaCl2 and KI) at all concentrations used. However, barium chloride was toxic to T. viride at 2-5% (w/v). The optimum temperature and pH for the antagonistic property of T. viride appeared to be 37 °C and 6.0 respectively. Conclusion, significance and impact of study: Inclusion of different carbon, nitrogen and salts increased the antagonistic activities of T. viride against S. rolfsii although lactose appeared to be the best carbon source while zinc nitrate and CaCl2 were the best nitrogen and salt respectively. Barium chloride was toxic to T. viride at 2-5% (w/v).

Optimization of submerged culture for biomass and polysaccaharide of Pleurotus ostreatus BPPTCC 6017 using response surface methodology

Aims: Polysaccharide of Pleurotus ostreatus is one of the fungal polysaccharide which has been widely studied, produced by extracting the fruiting body. An alternative method for producing polysaccharide of P. ostreatus directly from the mycelia instead of the fruiting body is through submerged culture. This study was aimed to determine the optimum submerged culture conditions for producing biomass and intracellular polysaccharide of the oyster mushroom. Methodology and results: P. ostreatus BPPTCC 6017 was collected from traditional mushroom farm in West Java, Indonesia. Submerged fermentation was conducted in 1000 mL medium (2 L flask). Four variables were tested: temperature, pH, agitation, and fermentation time, using central composite design of the response surface methodology. Mycelial biomass produced, was extracted to obtain water-soluble and alkali-soluble polysaccharide. Experimental data obtained were fitted to a second-order polynomial equation using multiple regression analysis and also analysed by appropriate statistical methods. The 3-D response surface plots derived from the mathematical models were applied to determine the optimum conditions: temperature 27.89 °C, initial pH medium 5.49, agitation 124.08 rpm, and fermentation time 11.44 days. The predicted results of the models were 33.75 g/L mycelia, 0.33 g/L water-soluble polysaccharide, and 0.64 g/L alkali-soluble polysaccharide. Those results were then verified on the optimum conditions, and produced 32.00±1.25 g/L mycelia, 0.29±0.01 g/L water-soluble polysaccharide and 0.60±0.02 g/L alkali-soluble polysaccharide, were close to the theoretical predictions. Conclusion, significance and impact study: The present study was a first effort to assess and obtain the optimum conditions for producing the biomass and polysaccharides of the strain P. ostreatus BPPTCC 6017 using submerged fermentation

Growth and Cultural Characteristics of Cordyceps cardinalis Collected from Korea

Cordyceps cardinalis was reported in Japan and the USA in 2004, and its fruiting bodies have recently been cultured in Korea. Herbarium specimens preserved at the Cordyceps Research Institute, Mushtech, Korea were revised and identified as C. cardinalis, based on morphological characters and conidial structures. Most of the C. cardinalis specimens were collected from Mt. Halla in Jeju-do. The effects of various nutritional sources and environmental conditions such as temperature and pH on mycelial growth of C. cardinalis were studied. Oatmeal agar, Martin's peptone dextrose agar, and Schizophyllum (mushroom) genetics complete medium plus yeast extract resulted in the best mycelial growth. Among carbon sources, cereals, and nitrogen sources, maltose, oatmeal, and peptone resulted in the best mycelial growth respectively. Mineral salts helped to increase growth rate but only resulted in thin mycelial density, similar to water agar. A temperature of 25degrees C and a pH of 7 resulted in the highest mycelial growth. Based on these results, a Cordyceps cardinalis composite medium (CCM) was formulated with 1% maltose, 2% oatmeal, 1% peptone, and 2% agar. Use of the CCM resulted in slightly better mycelial growth than that of other commonly used agar media. Only organic nitrogen sources imparted a reddish pigmentation to the agar media, but this character diminished after several subcultures. A 7 day culture duration resulted in the best mycelial growth.

Production of Aerial Conidia of Lecanicillium lecanii 41185 by Solid-State Fermentation for Use as a Mycoinsecticide

The production of aerial conidia of Lecanicillium lecanii 41185, a highly virulent fungus, by solid-state fermentation was studied for use as a biocontrol agent against aphids. Among several agro-industrial solid media, steamed polished rice was found to produce the highest amount of aerial conidia. The optimal conditions for aerial conidia production were determined to be a 28.5% moisture content in the rice, 25degrees C culture temperature, rice pH of 6.0, 75% ambient relative humidity, 4-dold seeding culture, 0.6% KNO3, and 12 d of culture time. The conidia yield increased from 5.7 x 10(9) conidia/g polished rice to 18.2 x 10(9) conidia/g polished rice following application of these optimized conditions.

On the optimal height for apple sorting table / 日本農村医学会雑誌

The optimal height of the working table for fruits-sorting in apple orchards was studied from the viewpoint of energy metabolism using model experiment, and actual condition of theapple-sorting table was surveyed. Results:<BR>1. Oxygen consumption per minute increased by the apple sorting work were measured about the seven kinds of table height (from 40 cm to 100 cm). Supposing that the height of the working table subtracted by (stature+height of footwear) is “x” and the oxygen consumption per minute increased by the work is “Y”, the relationship between these two values can be expressed as the following quadratic equation:<BR>y=0.226x<SUP>2</SUP>-20.91x+677.1<BR>Thus, it was found that the optimal height for apple sorting table was 46% of the stature including footwear height.<BR>2. The height of the fruits-sorting table used in apple orchards was usually 30-40% of the stature including footwear height of the workers, and this was found to be too low. This seems to have been caused by easygoing and perfunctory attitude or practices to the fruits-sorting work, e. g. to use the wooden boxes for apple as the substitutes for the fruits-sorting table.<BR>3. It is necessary to improve the table and to develop and propagate the better apple-sorting table from ergonomical viewpoint in order to reduce and eliminate the lumbago and fatigue among the workers engaging in the apple-sorting work.

THE STUDY OF THE OPTIMUM CONDITION OF TWO FREEZING METHODS FOR PRESERVATION OF RABBIT EMBRYOS / 解剖学报

This paper reports the effects of the temperature control freezing and the liquid nitrogen vapour freezing on the viability of rabbit morulae. After rapid thawing, 70.27% embryos were able to develope well in vitro in the temperature control freezing group and in the liquid nitrogen vapour freezing group, the developmental rate was 80.56% when the freezing medium contained higher concentration of glycerol. After synchronous embryos were transplanted, the birth rate was 13.64% and 13.33%, respectively, in both freezing groups, and 11.11% in the control group. The results indicate that both freezing methods have almost the same good results, but the method of liquid nitrogen vapour freezing is more useful than the temperature control freezing method in some aspects.