Examining the Osmotic Response of Acidihalobacter aeolianus after Exposure to Salt Stress

Acidihalobacter aeolianus is an acidophilic, halo-tolerant organism isolated from a marine environment near a hydrothermal vent, an ecosystem whereby levels of salinity and total dissolved salts are constantly fluctuating creating ongoing cellular stresses. In order to survive these continuing changes, the synthesis of compatible solutes—also known as organic osmolytes—is suspected to occur, aiding in minimising the overall impact of environmental instability. Previous studies on A. aeolianus identified genes necessary for the accumulation of proline, betaine and ectoine, which are known to act as compatible solutes in other halophilic species. In this study, the impact of increasing the osmotic stress as well as the toxic ion effect was investigated by subjecting A. aeolianus to concentrations of NaCl and MgSO4 up to 1.27 M. Exposure to high concentrations of Cl- resulted in the increase of ectC expression in log-phase cells with a corresponding accumulation of ectoine at stationary phase. Osmotic stress via MgSO4 exposure did not trigger the same up-regulation of ectC or accumulation of ectoine, indicating the transcriptionally regulated response against osmotic stress was induced by chloride toxicity. These findings have highlighted how the adaptive properties of halo-tolerant organisms in acidic environments are likely to differ and are dependent on the initial stressor.

MICROENCAPSULATION OF L. FERMENTUM ISOLATED FROM TRADITIONAL DAIRY PRODUCTS AND ITS STABILITY ON EXPOSURE TO SIMULATED GASTROINTESTINAL CONDITIONS

The physiological state of food may affect the survival potential of health promoting microorganisms. The current research was thus undertaken for comparing the invitro stability of two similar species of L. fermentum isolated from two different dairy products. The isolates were analyzed for their viability after microencapsulation in sodium alginate and were also compared using the non-encapsulated strain in simulated gastric and intestinal conditions. Viability of the cultures were also compared against reference standard (i.e) Lactobacillus acidophilus procured from MTCC Chandigarh. The percentage log reduction of non- encapsulated cultures i.e curd, raw milk and MTCC was 58.32%,58.28%,58.43% while that of encapsulated cultures was 10.19%, 10.03% and 11.18% as observed in gastric juice. The log reduction of non -encapsulated cultures as observed was 3.80%, 3.10% and 2.23% for curd raw milk and MTCC cultures respectively while that of encapsulated cultures was 1.54%, 1.52% and 1.16%in simulated intestinal conditions. The raw milk isolate was found with slightly better adaptation in response to the viability both in case of gastric and intestinal juice. The result thus justifies the physiological state of food which may affect the osmotic response and stress of similar microflora although isolated from two different food consortiums.

PROFIL OSMOTIK GELONDONGAN IKAN BANDENG (Chanos chanos Forsskal) SELAMA PROSES KULTIVASI DI TAMBAK BANDENG DESA WONOREJO KABUPATEN KENDAL

Milkfish is euryhaline fish that can live in wide range salinity, so it will affect with osmoregulation processes. This research aimed to examine the osmotic response of milkfish fingerling during cultivation processes in brackishwater ponds at Wonorejo Village district of Kendal. The research was conducted on July-October 2016. The cultivation process of milkfish fingerling has been cultured for 60 days in 2000 m2 brackishwater pond. The initial density of milkfish larvae was 100 individuals /m2 with a lenght size of 10 mm on average and 15 days old. Samples of milkfish fingerling were taken on the 20th, 40th and 60th days, the number of samples was 3 individuals every size. The measurement result of blood osmolarity was 460, 05 to 490.10 mOsm / l H2O higher than media osmolarity 38,98 – 194,5 mOsm/l H2O. The osmotic response of milkfish fingerling were hyperosmotic to the hypotonic environment and osmoregulator fish.

PENGARUH SALINITAS BERBEDA TERHADAP RESPON OSMOTIK, REGULASI ION DAN PERTUMBUHAN IKAN SIDAT (Anguilla sp.) FASE ELVER SELAMA MASA AKLIMASI DAN KULTIVASI

Salinitas yang sesuai dengan kebutuhan tubuh ikan diperlukan untuk efisiensi penggunaan energi tubuh. Penelitian ini bertujuan untuk mengetahui respon osmotik, regulasi ion dan pertumbuhan elver ikan sidat pada salinitas berbeda. Penelitian dan penulisan dilaksanakan dari Maret-Juli 2018 menggunakan rancangan acak lengkap dengan 3 level salinitas dan 3 kali ulangan. Elver ikan sidat dipelihara pada akuarium dengan ukuran 30 x 20 x 20 cm yang dilengkapi aerator dan pipa peralon sebagai shelter. Elver ikan sidat dipelihara selama 42 hari dengan pergantian air media dan pemberian pakan setiap 2 hari sekali. Pengukuran panjang dan bobot tubuh dilakukan pada awal dan akhir penelitian. Osmolaritas media dan osmolaritas haemolymph di ukur menggunakan osmometer. Uji pendahuluan dilakukan untuk menentukan salinitas yang digunakan pada uji utama. Hasil yang diperoleh yaitu rata-rata osmolaritas media dan haemolymph pada salinitas 0 ‰, 2‰ dan 4 ‰ berturut-turut bernilai 1,7 ‰ mOsm/l H2O, 60,28 mOsm/l H2O, 116,4 mOsm/l H2O dan 47,56 mOsm/l H2O, 62,28 mOsm/l H2O, 68,1 mOsm/l H2O. Rata-rata panjang tubuh dan penurunan bobot tubuh pada salinitas 0 ‰, 2‰ dan 4 ‰ berturut-turut yaitu 1,05 cm, 2,07 cm, 0,84 cm dan 3,55 g, 0,82 g, 2, 65 g. Konsentrasi ion rata-rata pada salinitas 0 ‰, 2‰ dan 4 ‰ berturut-turut bernilai 0,27 g/l, 3,25 g/l dan 0,21 g/l. Berdasarkan hasil penelitian dapat diketahui bahwa salinitas isoosmotik dan tingkat kerja osmotik terendah pada salinitas 1,97 ‰. Pertumbuhan panjang tertinggi dan penurunan bobot tubuh terendah berada pada salinitas 2 ‰ serta konsentrasi ion tertinggi pada salinitas 2 ‰. Salinity that suits with the fish needs is necessary for the efficient use of energy in the body. This study aims to determine the osmotic response, ion regulation and elver eel fish growth at different salinity. The research was conducted from March to July 2018 and used a complete randomized design with 3 levels of salinity and 3 replications. Elver eel is kept in aquarium with size 30 x 20 x 20 cm which is equipped with aerator and pipe as shelter. Elver eel is maintained for 42 days with water change media and feeding every 2 days. Measurements of length and body weight were performed at the beginning and end of the study. Media osmolarity and haemolymph osmolarity are measured using an osmometer. The experiment preliminary aims to determine salinity that use at experiment prime.The results obtained were the mean of media osmolarity and haemolymph at salinity of 0 ‰, 2 ‰ and 4 ‰ respectively were 1.7 ‰ mOsm / l H2O, 60.28 mOsm / l H2O, 116.4 mOsm / l H2O and 47,56 mOsm / l H2O, 62.28 mOsm / l H2O, 68.1 mOsm / l H2O. Average of body length and decrease of body weight at salinity of 0 ‰, 2 ‰ and 4 ‰ respectively were 1.05 cm, 2.07 cm, 0.84 cm and 3.55 g, 0.82 g, 2.65 g. The mean ion concentrations in the salinity of 0 ‰, 2 ‰ and 4 ‰ were 0.27 g / l, 3.25 g / l and 0.21 g / l respectively. Based on the research results it can be seen that the isoosmotic salinity and the lowest osmotic work rate are at salinity 1.97 ‰. The highest growth length and the lowest body weight decrease is at 2 ‰ salinity and the highest ion concentration is at 2 ‰ salinity.