Natural halogenated compounds (halometabolites) are produced mainly by marine organisms, including marine Actinobacteria. Many commercially important compounds for pharmaceuticals contain halogen, and the halogen is responsible for the physical and chemical properties as well as bioactivities and toxicities. In the exploration of marine environment that is supported by advanced structure elucidation, varied panel bioassays and high-throughput screening have accelerated number of halometabolites isolated from marine Actinobacteria to date. The metabolites exhibited unique structures and promising bioactivities. This review focuses on the chemodiversity and bioactivities of marine halometabolites from marine Actinobacteria reported in the last 15 years (2003–2018).

Seaweeds produce great variety of metabolites benefit for human. Red seaweeds (Rhodophyta) are well known as producer of phycocolloids such agar, agarose, carragenan and great variety of secondary metabolites. This review discusses the red algal secondary metabolites with antibacterial activity. The chemical constituents of red algae are steroid, terpenoid, acetogenin and dominated by halogenated compounds mainly brominated compounds. Novel compounds with intriguing skeleton are also reported such as bromophycolides and neurymenolides. In summary, red seaweeds are potential sources for antibacterial agents and can serve as lead in synthesis of new natural medicines.

Bakteri asam laktat telah lama dikembangkan sebagai probiotik. Penentuan kondisi lingkungan yang optimum untuk pertumbuhan sel serta asam organik memberikan gambaran aktivitas optimum untuk kinerja probiotik baik dalam sistem fisiologi inang maupun dalam sistem bioproses untuk produksi sel dan metabolit. Penelitian ini bertujuan untuk mengetahui pengaruh faktor lingkungan (pH, suhu dan salinitas) terhadap pertumbuhan dan produksi total asam organik tiga isolat bakteri asam laktat yang telah diseleksi dari intestinum udang penaeid. Eksperimen menggunakan  medium deMan, Rogosa and Sharpe (MRS) cair. Perlakuan pH awal meliputi  nilai pH 4, 5 dan 6. Perlakuan suhu meliputi suhu 25, 30 dan 35OC serta perlakuan salinitas  meliputi salinitas 0,75 %, 1,5 % dan 3 %.  Setiap interval 6 jam dilakukan pengambilan sampel kultur bakteri dan penghitungan pertumbuhan berdasarkan perubahan optical density (pada panjang gelombang 600 nm) sedangkan produksi asam laktat dianalisis dengan metode titrimetrik menggunakan NaOH 1 N sebagai larutan titrasinya. Berdasarkan hasil penelitian disimpulkan bahwa suhu, pH awal dan salinitas berpengaruh terhadap pertumbuhan dan produksi asam organik. Nilai kondisi lingkungan terbaik untuk pertumbuhan dapat berbeda dengan nilai terbaik untuk produksi asam organic. Hal ini ditunjukan oleh nilai laju pertumbuhan dan produksi asam laktat tertinggi dari tiga isolat uji terjadi pada suhu, pH awal dan salinitas yang berbeda.  Isolat L12 tumbuh optimum pada suhu 30oC, pH awal 6 dan salinitas 0,75%. Isolat L14 tumbuh optimum pada suhu 30oC, pH awal 6 dan salinitas 1.5%. Isolat L 21 tumbuh optimum pada suhu 30 oC, pH awal 6 dan salinitas 1.5%. Kata kunci: bakteri asam laktat, suhu, pH, salinitas, asamorganik, pertumbuhan, Lactic acid bacteria are widely distributed in intestinal tracts of various animals where they live as normal flora.Strains of lactic acid bacteria are the most common microbes employed as probiotics, The optimum condition for growth are important to mass production and to determined parameters most suitable for growth. The effects of  temperature, pH and salinity on the growth and production of lactic acid from the three shrimp intestinal lactic acid bacteria isolates were conducted using bacth culture in a flask. These variables for growth were determined based on the growth curves and lactic acid production. Data from the flask batch experiment demonstrated that the best initial pH and temperature  for growth of isolat L12 ,L14 and L21 were found to be pH 6 and 30 OC.  Salinity (NaCl concentration) 0,75% were the best for growth of isolat L12. Salnity  1,5 % were best for growth of isolat L14 and L21. Key words : growth, temperature, pH, salinity, lactic aid bacteria

The objective of this research was to know the effectiveness of polyvalen  Vibrio vaccine to control vibriosis in humpback grouper (Cromileptes altivelis). The effectiveness of vaccine was evaluated by the survival rate (SR), relative percent survival (RPS), mean time to death (MTD) as well as growth rate of vaccinated fish. This research consisted of 4 treatments (control, injection, immersion, and oral vaccinations) in quadruplicates. Injection  vaccination was conducted by intraperitoneal injection of polyvalen vaccine at 107 cells/fish. Immersion vaccination was done by immersing the fishes at 107 cells/ml for 30 minutes. Oral administration of vaccine was also carried out  at 107 cells/fish. One week after the first vaccination, second vaccination (booster) was carried out at the same dosage and by the same administration. One week after the second vaccination, fishes were challenged with 3.16x104 cells/fish of Vibrio ordalii 3J by intraperitoneal injection, and reared for 20 days post infection. Results indicated that polyvalen Vibrio vaccine increased SR (P<0.01) up to 100%. Vaccination was also able to delay MTD of fishes. However, the vaccination was not influence the growth rate of fish.

African catfish (Clarias sp.) is one of important freshwater fish which prefer consumed by people due to many advantages. Aeromonas sp. bacteria are dangerous patogen for freshwater fishes. This objective of the research was to isolate, identify and determine pathogenicity of Aeromonas sp. bacteria from African catfish from District Ngawi. The samples of catfish with 20 - 25 cm length showing clinical signs disease were obtained from three sub districts. Bacteria were isolated from kidney and inoculated into GSP medium. Characterization and identification through morphology of bacterial colonies, cells and biochemical test. Postulate Koch was conducted to verify abaility to couse disease. Pathogenicity was analyzed by determination of value of Lethal Dosage-50 on catfish on 7 - 9 cm length. The result showed that the disease symptoms of fish infected by the bacteria were skin ulcer, abdominal swelling and kidney damage. Fifteen bacterial isolates were collected which five, six and four isolates were from Kecamatan Karang Jati, Geneng dan Paron.sub-district respectively. The result showed 12 isolates (GKJ1, GKJ3, GKJ4, GGN1, GGN2, GGN3, GGN4, GGN5, GGN6, GPR2, GPR3 and GPR4) were identified as Aeromonas hydrophila. Three isolates (GKJ2, GKJ5 and GPR1) were identified as A. salmonicida. Isolate of A. hydrophila GKJ1, GKJ4, GGN2, GGN5, GPR2 and GPR4 were virulent to African catfish with LD50 values of 1,55 x 105, 3,89 x 105, 7,24 x 105, 2,39 x 105, 6,61 x 104 and 1,95 x 104 cfu/fish.