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Journal : HAYATI Journal of Biosciences

Selective Media for In Vitro Activity Evaluation of Bacterial Biocontrol Against Pathogenic Vibrio ISNANSETYO, ALIM; MUHTADI, .; ISTIQOMAH, INDAH; NITIMULYO, KAMISO HANDOYO; TRIYANTO, .
HAYATI Journal of Biosciences Vol 18, No 3 (2011): September 2011
Publisher : Bogor Agricultural University, Indonesia

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Abstract

In vitro activity test is a critical evaluation to screen the potential biocontrol agent. We developed a selective medium for quantitative in vitro activity evaluation of bacterial biocontrol agents against pathogenic Vibrio in aquaculture. Sensitivity test of bacterial biocontrol and Vibrio spp. to nine antibiotics showed that oxytetracycline inhibited the growth of Vibrio spp., but did not inhibit the growth of the bacterial biocontrol. This selective inhibition activity of oxytetracycline suggested this antibiotic might be supplemented to establish a selective medium. The MIC of oxytetracycline against V. harveyi, V. parahaemolyticus, and V. algosus were 120, 250, and 120 mg/ml, respectively. These concentration did not inhibit the growth of bacterial biocontrols. Therefore, oxytetracycline was supplemented at 250 µg/ml in Zobell agar medium. This medium was used as a selective medium to enumerate the density of bacterial biocontrol. In vitro activity test of bacterial biocontrol (RLP1) against V. parahaemolyticus showed that strain RLP1 at density of 104 and 106 cells/ml was able to kill V. parahaemolyticus during 6 h incubation. At lower density, 102 cells/ml, this bacterial biocontrol agent was able to kill the pathogenic Vibrio during 12 h incubation. This study discovered a selective medium for the bacterial biocontrol and Vibrio spp. and provided the results of its application in the evaluation of in vitro activity of a bacterial biocontrol agent against V. parahaemolyticus. The results also revealed that strain RLP1 is a potential bacterial biocontrol against vibriosis in marine aquaculture.
Independent Effects of Temperature, Salinity, Ammonium Concentration and pH on Nitrification Rate of the Ariake Seawater Above Mud Sediment ISNANSETYO, ALIM; GETSU, SAI; SEGUCHI, MASAHIRO; KORIYAMA, MASUMI
HAYATI Journal of Biosciences Vol 21, No 1 (2014): March 2014
Publisher : Bogor Agricultural University, Indonesia

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Abstract

The Ariake Sea located in the west parts of Kyushu Island is a semi-closed and macro-tidal shallow sea, and has the largest tidal flat in Japan. A large mud tidal flat with a productive ecosystem found along the western shoreline of the sea makes this area ideal as a major production site of nori (Porphyra yezoensis) in Japan. We determined the independent effect of temperature, salinity, ammonium concentration and pH on nitrification rates (NR) in the Ariake seawater above the mud sediment. The NR was determined by measuring accumulation of NO2-N production after adding sodium chlorate, an inhibitor of NO2-N to NO3-N oxidation. NRs were relatively high at 20-35 oC (optimum at 29.5 oC), but the rates were very low at 5, 10, and 40 oC. NRs increased sharply when increasing the salinity from 13 to 20 ppt, but it decreased drastically at salinity levels more than 35 ppt (optimum at 19 ppt). The relationship between ammonium concentration and NR showed a typical kinetic curve of enzymatic reaction with the maximum NR (Vmax) of 0.029 mM N.h-1 at 200 mM NH4-N (the half saturation constant (Ks) = 35 mM NH4-N). High NRs were determined at pH 7.5-8.0 (optimum pH 7.8). This is the first report on the independent effects of temperature, pH, salinity and NH4-N concentration on the NR of seawater, specifically the Ariake seawater.
Distribution of Ammonium-Oxidizing Bacteria in Sediment with Relation to Water Quality at the Musi River, Indonesia Melki, Melki; Isnansetyo, Alim; Widada, Jaka; Murwantoko, Murwantoko
HAYATI Journal of Biosciences Vol 25, No 4 (2018): October 2018
Publisher : Bogor Agricultural University, Indonesia

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Abstract

The Musi River is located in the southern Sumatra, Indonesia. Most of activities, i.e. agricultural, industrial, and urban activities are considered as being major sources of chemicals and nutrients with their waste products effluent into the river. Nitrification, the microbial oxidation of ammonia to nitrite and nitrate, occurs in a wide variety of environments and naturally remove anthropogenic N pollution. The purpose of this research was to determine of distribution of ammonium-oxidizing bacteria (AOB) in sediment with relation to water quality at the Musi river area. This study was conducted on rainy and dry season 2016 at five sampling sites from the freshwater to seawater at high and low tide conditions, the sampling sites are station St1 (Gandus), station St2 (Palembang city), station St3 (Upang), station St4 (Sungsang), and station St5 (Sea). Sediment samples were collected from the surface layer by using an Ekman grab. Some water quality such as salinity, temperature, pH, and dissolved oxygen (DO) were directly analyzed in the field, while other water quality such as NH4-N, NO2-N, and NO3-N were analyzed in the laboratory. The Density of AOB was determined by the most probable number of (MPN) method. The PCA was used to correlate variations of the AOB with physicochemical properties using software Xlstat. The results showed that the physicochemical properties had a range of salinity of 0 to 20 ppt, temperature of 29.21 to 31.82oC, pH of 4.88 to 7.93, DO of 3.44 to 11.33 mg/l, NH4-N in sediment of 0.04 to 0.87 mg/l, NO2-N in sediment of 0.01 to 1.77 mg/l, NO3-N in sediment of 0.09 to 2.08 mg/l. The density of AOB ranged from 7.2 x 102 to 6.1 x 103 cells/g sediment. Principal component analyses showed that temperature, pH, DO, and concentrations of nutrient contributed to density of AOB.
Independent Effects of Temperature, Salinity, Ammonium Concentration and pH on Nitrification Rate of the Ariake Seawater Above Mud Sediment ISNANSETYO, ALIM; GETSU, SAI; SEGUCHI, MASAHIRO; KORIYAMA, MASUMI
HAYATI Journal of Biosciences Vol 21, No 1 (2014): March 2014
Publisher : Bogor Agricultural University, Indonesia

Show Abstract | Original Source | Check in Google Scholar | Full PDF (915.094 KB)

Abstract

The Ariake Sea located in the west parts of Kyushu Island is a semi-closed and macro-tidal shallow sea, and has the largest tidal flat in Japan. A large mud tidal flat with a productive ecosystem found along the western shoreline of the sea makes this area ideal as a major production site of nori (Porphyra yezoensis) in Japan. We determined the independent effect of temperature, salinity, ammonium concentration and pH on nitrification rates (NR) in the Ariake seawater above the mud sediment. The NR was determined by measuring accumulation of NO2-N production after adding sodium chlorate, an inhibitor of NO2-N to NO3-N oxidation. NRs were relatively high at 20-35 oC (optimum at 29.5 oC), but the rates were very low at 5, 10, and 40 oC. NRs increased sharply when increasing the salinity from 13 to 20 ppt, but it decreased drastically at salinity levels more than 35 ppt (optimum at 19 ppt). The relationship between ammonium concentration and NR showed a typical kinetic curve of enzymatic reaction with the maximum NR (Vmax) of 0.029 mM N.h-1 at 200 mM NH4-N (the half saturation constant (Ks) = 35 mM NH4-N). High NRs were determined at pH 7.5-8.0 (optimum pH 7.8). This is the first report on the independent effects of temperature, pH, salinity and NH4-N concentration on the NR of seawater, specifically the Ariake seawater.