Triyanto

Phenotype and genotype of lactic acid bacteria (LAB) isolated from the tiger grouper Epinephelus fuscoguttatus alimentary tract

Lactic acid bacteria (LAB) have been isolated successfully from the tiger grouper Epinephelus fuscoguttatus intestine. However, their genus or species have not been identified. Therefore, the objective of the present study was to characterize the three isolated LAB (KSBU-12C, KSBU-5Da, and KSBU-9) based on their phenotype and genotype. The LAB phenotype was examined by observing morphological features including cell morphology, spore production and motility. The physiological tests were performed in 6.5% NaCl at the temperatures of 10 oC and 45 oC, and the biochemical tests were evaluated based on the production of enzymes catalase, oxidase and arginine dehydrolase, following the Standard Analytical Profile Index, API 50 CH kit. The genotype was examined based on 16S rDNA gene sequence analysis , and the products were analyzed using the BLAST (Basic Local Alignment Search Tool) NCBI database. The three isolates (KSBU-5Da, KSBU-12C, and KSBU-9) were categorized into the genus Enterococcus. 16S rDNA sequence analysis indicated that the isolates had 99% similarity to E. hirae ATCC 9790, registered in GenBank with accession number NR_075022.1. It was concluded that the three LAB isolates taken from the tiger grouper Epinephelus fuscoguttatus are E. hirae.

ISOLASI DAN KARAKTERISASI BAKTERI PENDENITRIFIKASI YANG DIISOLASI DARI LUMPUR KAWASAN MANGROVE

The aim of this research is to isolate denitrifying bacteria which have the highest activity to reduce nitrate. The sources of the denitrifying bacteria were mangrove sediment collected from Cilacap Regency, Central Java and Indramayu Regency, West Java. Basalt medium containing KNO 3 as a source of nitrogen was used for isolating the denitrifying bacteria. Double layer agar was used for making anaerob condition. Fourty-one isolates were obtained at the first step of the isolation, 29 of them have nitrate reduction activity at a range of 0.77-95.62%. Three isolates, i.e. D19.2, DR2.1 and D27.3 having the highest activity were selected for further examination. The selected isolates were characterized and identified. Characterization includes colony and cell morphology, Gram staining, motility, spore staining and biochemical tests as catalase and oxidase. Identification was done by using profile matching to Bergey’s Manual of Determinative Bacteriology. The results indicate that isolate D19.2 and D27.3 have similarities to the characters of genus Listeria , whereas isolate DR2.1 has similarities to the characters of genus Propionibacterium . All of the selected isolates were able to grow in a medium having NaCl concentration at a range of 0.5-3.5% and pH range of 5-8. Observation of nitrate reduction ability of the isolates during five days incubation shows that isolate DR2.1 has the highest denitrifying activity. The selected isolates can be used as bioremediation agents for controlling nitrate pollution in brackish water pond.

PENGEMBANGAN METODE LOOP-MEDIATED ISOTHERMAL AMPLIFICATION OF DNA DAN APLIKASINYA UNTUK DETEKSI KOI HERPES VIRUS PADA BEBERAPA JENIS IKAN

The purposes of this experiment were to establish loop-mediated isothermal amplification of DNA ( LAMP) method and its application to observe the presence and duration of koi herpes virus ( KHV) in freshwater fishes after infection. The infection was carried out using 4-6 cm length of java barb ( Barbodes gonionotus ), grass carp ( Ctenoparingodon idella ), gold fish (komet) ( Carassius auratus ), tambaqui ( Colossoma macropomum ) and koi ( Cyprinus carpio koi) fishes. Fishes were infected intraperitoneally with KHV inoculums and 2 fishes were sampled everyday. DNA was extracted from gill and used for diagnosis with LAMP assays. The result of this experiment showed LAMP assay can be established and gave 100 times more sensitive than conventional PCR assay. Koi was confirmed as a host of KHV. Java barb, tambaqui, gold fish and grass carp can serve as vector for KHV and the presence of KHV was detected in java barb and tambaqui for 4 days, goldfish and grass carp for 5 days after infection.

ISOLASI, KARAKTERISASI DAN UJI INFEKSI BAKTERI PROTEOLITIK DARI LUMPUR KAWASAN HUTAN BAKAU

This research was aimed to isolate proteolytic bacteria that have high ability to hydrolize protein. The sources of bacterial samples were collected from mangrove sediment in Indramayu and Cilacap Regency. Collwel SWYE Modification Agar medium and Skim Milk Agar Medium, which contain pepton and casein, were used for isolating the bacteria. Forty isolates having proteolitic activity were obtained. Three isolates, i.e. Ps.23.1, Ps.27.3 and Ps.23.2, having the highest activity were selected. The selected isolates were able to grow at pH range of 5 to 8. They were also able to grow at NaCl concentration of 0.5-3.5%. Intramuscular injection test on white shrimp (Lithopenaeus vannamei) shows that Ps.23.1 and Ps.23.2 were not pathogenic to shrimp. On the other hand, Ps.27.3 was indicated to cause disease on shrimp. These results indicated that isolates Ps.23.1 and Ps.23.2 potentially can be used as inoculant for bioremedation of brackish water pond. Isolate Ps.23.1 was characterized to be an aerobic, nonmotile, short rod, gram negative bacteria having catalase and oxidase activities. It produced yellowish, circulair, entire colonies. Isolate Ps.23.2 was characterized to be an aerobic, motile, rod, spore forming, gram positive bacteria having catalase and oxidase activities.