Judul: Study of Chemoreaction Drying with Calcium Oxide and Its Impact on the Stress and Damage of Saccharomyces cerevisiae Culture, Kajian pengeringan kemoreaksi dengan kalsium oksida serta dampaknya terhadap stress dan kerusakan kultur Saccharomyces cerevisiae
Abstrak: The objective of the research was to study the parameters of the drying process and their effects on the viability of dried Saccharomyces cerevisiae culture. These parameters include the pattern of water isotherm sorption, the critical water contents, stress and mortality on a variety of bound water conditions, as well as morphological and micro-structural changes of damaged and leaked stressed cells. Layer thickness of the sample and high ratio used of calcium oxide speed up the drying process. Using a calcium oxide to sample ratio of 10:1 (w/w) for drying, 1.3 mm thickness of sample with 78-80% water content required 24 hours to dry to a final 4.42 % water content. The viability and cell content of the final product were 72% and 109 cells per g dried sample respectively. A sigmoid curve sorption isotherm pattern consist of 3 bound water regions of the dried yeast culture was similar to that of common dried foods. In the primary area most of the dried cells were dormant, in the secondary area the majority of the cells were under stress condition, while in the tertiary area a lot of them died. Likewise, the viability curve up to aw 0.2 was very low as due to high number of dormant cells, in between aw 0.2 - 0.6 sharply increased due to decreasing number of dormant cells, in between aw 0.6-0.75 sharply decreased due to increasing number of dying cells, and above 0.75 the cells was dying off to totally died. As shown by SEM observation, normal cells were oval-shaped with a smooth surface. In the primary region the dried cells showed and oval to round shape and small number of deformed cells, in the secondary region wrinkled surface and some number of deformed cells, while in the tertiary region the cells were sticky with wrinkled surface and most cells were damage. Meanwhile, TEM observation showed that the cells in the primary region had a well-defined, thick and solid cell wall with smooth surface with visible nuclei. In the secondary region the cells showed a wrinkled surface with less visible nuclei, while the wall was thin and cracked in some places. In the tertiary region the most number of cells were damaged, the remaining defined cells were flat, empty, irregular shape and no nuclei were visible. The increasing cell damaged was mainly due to the leaking out of cell or cytoplasm and the nuclear content through the damage cell wall. This was shown by increased electrical conductivity as well as the nucleic acid, nucleotide, protein and amino acids content of the cell-free supernatant from the culture. The Ca++ and K+ content of the cell mass decreased due to the leakage out of cell content. Sharp increase of K+ in secondary region of bound water was due to cell wall leakage, while high level of K+ in the tertiary region of bound water was due to high lysis of the cells with increased cell content damage.
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Judul: Penggunaan pGFPuv Mutan Untuk Mempelajari Pengaruh Pengeringan Pada ketahanan hidup Cronobacter sakazakii Dalam Jagung.
Abstrak: Cronobacter sakazakii is an emerging Gram-negative foodborne bacterial pathogen regarded as the causative agent of meningitis and necrotizing enterocolitis in certain groups of infants. Several isolates of C C. sakazakii have been obtained from food samples in Indonesia and transformation with a Green Fluorescent Protein (GFP) plasmid has produced C. sakazakii pGFPuv mutants with growth pattern similar to that of the wild-type strains. Therefore, they are potential to be used for studying C. sakazakii behaviour without the need to suppress other microorganisms and the use of diagnostic media. The research activities focused on the following objectives : to study the effect of drying on water content and water activity of maize and to evaluate the survival of C. sakazakii pGFPuv as well as other naturally occurring microorganisms in maize during drying. Maize kernels with moisture content of 40% (d.b) were inoculated with C. sakazakii pGFPuv mutant such that the initial concentration in the maize was CFU/g and drying was performed at temperatures of 42 ºC, 46 ºC and 50 ºC for ten days in a drying chamber. Every day the maize samples were taken and the water content were analyzed using oven method while water activity by Aw meter. Total Plate Count and C. sakazakii surviving in the maize were enumerated by standard plate count. The survival rate of C. sakazakii during drying was determined by the slope of linear regression from C. sakazakii survival curve. The results showed that the fate of decrease of C. sakazakii during the rapid decline of water content and Aw can be divided into three phases, i.e. logarithmic decrement, static growth and the final decline. The critical water activity for these pathogenic bacteria was in the range of 0.85-0.86. Observation by SEM showed that C. sakazakii GFPuv form colonies on the surface of corn and the tip cap. This study showed that of C. sakazakii pGFPuv can be used to study the survival of C. sakazakii during corn drying.
Keyword: Cronobacter sakazaki, pGFPuv, maize, survival, drying, water activity

Judul: Biologi Troides helena helena dan Troides helena hephaestus (Papilionidae) di Penangkaran
Abstrak: Indonesia adalah negara kepulauan beriklim tropik dengan berbagai tipe habitat dan ekosistem. Kondisi alam Indonesia merupakan habitat yang cocok bagi berbagai fauna termasuk kupu-kupu. Diperkirakan sekitar 4 000 – 5 000 jenis kupu-kupu terdapat di Indonesia. Troides helena merupakan salah satu kupu-kupu yang memiliki kombinasi warna sayap indah dan berukuran besar, sehingga menarik perhatian kolektor kupu-kupu. T. helena termasuk satwa yang diperdagangkan dan telah memasukkan devisa dari subsektor kehutanan Indonesia. Untuk mencegah dari kepunahan karena eksploitasi yang berlebihan, maka pemerintah melindungi T. helena melalui PP No. 7 Tahun 1999. Semua genus Troides masuk dalam daftar Appendix II CITES, sehingga perdagangan jenis ini harus merupakan hasil budi daya di penangkaran.
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