*Author for Correspondence.
Department of Cell and Molecular Biology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400 UPM-Serdang, Selangor, Malaysia.
T+6896775x+6Tel: +60 3 89467475;Fax:+60 3 89467510; Email:This email address is being protected from spambots. You need JavaScript enabled to view it.

Abstract.
Rice grain filling is a critical factor that affects yield. In this study, we analyzed the transcripts from rice panicles of the indica rice cultivar MR84 during reproductive and grain filling stages by using expressed sequence tag (EST) approach. Subtractive hybridizations were conducted using three pools of mRNA encompassing panicle initiation, booting, heading, flow­ering, pollination, fertilization, early/mid and late grain developmental phases. A total of 2366 clones were obtained from these subtractive hybridizations and 718 of them were sequenced. Approximately 36% of the sequenced cDNAs from rice panicles during panicle initiation to heading encoded for pollen allergens, whereas, the remaining ESTs encoded proteins involved in metabolism, transportation, gene expression and other functions. Most of the ESTs from heading to milk stage were storage proteins or involve in metabolisms, whereas, majority of the gene sequences from milk stage to maturation encoded putative storage proteins (61 %) e.g. glutelins and prolamins. Starch is the main component of rice seed dry weight and its biosynthesis largely drives rice yield. Herein, a partial cDNA sequence (I-AGPS1) for the plastidial form of ADP-glucose pyrophosphory­lase small subunit, which is involved in the rate-limiting step of starch biosynthesis in higher plants, was isolated from MR84. This gene was preferentially expressed in the grains of milk and dough stage, but unlike its homolog from japonica cultivar, was undetected in rice leaves.

*Author for Correspondence.
Dept. of Food Science, Faculty of Food Sci­ence and Technology, Universiti Putra Malaysia, 43400 UPM, Ser­dang, Selangor, Malaysia.
Tel:+603 89468371; Fax:+603-89423552; Email: This email address is being protected from spambots. You need JavaScript enabled to view it.

Abstract.
Polyphenol oxidase (PPO) and peroxidase (POD) activities were visualized histochemically at the cellular level of a young and a mature tree of Metroxylon sagu employing histochemical technique. In the mature tree, intense PPO activity was observed in the cell wall of the parenchyma and xylem cells when visualized under light microscope. Pith collected from the young tree showed PPO activity in the amyloplast and mitochondria inner membrane and to some extent in the golgi complex and endoplasmic reticulum. Whereas, a positive POD reaction product was visualized in the cell wall, peroxisomes and to some extent in the cytoplasm and the vacuole. The localization of PPO activity in the amyloplast and being adsorbed by the starch granules is in line with the general view that enzyme is involved in the browning of sago starch.

^*Author for Correspondence.
Institute of Biological Sciences,
Faculty of Science,
University of Malaya,
Kuala Lumpur 50603, MALAYSIA.
Tel: 6-03- 7967-6740
Fax:6-03-7967-4178
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Abstract.
Ammonium uptake kinetics of low specific growth rate cultures of Pseudomonas putida PGA1, a gram negative fluorescent pseudomonad, which is an important producer of poly(3-hydroxyalkanoates) (PHA) molecules, were studied. The ammonium uptake follows a first-order kinetics model, indicating that the micro-organism’s specific uptake rate of ammonium and its growth would increase as the ammonium ion concentrations become higher. Optimal ammonium uptake and growth rates were observed at 0.1 gL-¹ ammonium ion in aqueous medium. It also indicated that the ammonium transport mechanism is probably inducible by ammonium concentration. The limit of ammonium ion level increase before cells stop growing completely is given by the substrate inhibition constant, K_i which equals to 1.2 gL-¹ ammonium ion concentration.

^*Author for Correspondence.
Institute of Biological Sciences,
Faculty of Science,
University of Malaya,
50603 Kuala Lumpur, Malaysia.
Tel: +603-79674380
Fax: +603-79-674-178
E-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.

Abstract.
Regenerated plants were established using male inflorescence of Musa acuminata cv. Berangan. Explants were cultured on Murashige and Skoog (MS) solid medium supplemented with three different concentrations of 6- benzylaminopurine (BAP). After 2 weeks, whitish bud-like structures (WBLS) were obtained and MS media supplemented with 70.0 µM BAP was observed as the best media for the growth of WBLS. After 3 months, shoot-like structures emerged and MS media supplemented with 31.0 µM BAP gave a large number of shoot formation. Normal looking plantlets were obtained within 4 - 6 months with an average of 80 - 130 shoots regenerated from each male inflorescence. Random amplified polymorphic DNA (RAPD) was carried out to determine the clonal fidelity on in vitro Musa acuminata cv. Berangan micropropagated from male inflorescence derived from the same mother plant. Eighteen arbitrary decamer primers were used to amplify DNA from in vitro plants materials. All RAPD profiles from regenerated plants were monomorphic thus no somaclonal variation was detected. A total of 81 bands were scored from PCR amplification of genomic DNA from 15 micropropagated plants. This was further confirmed by the value of similarity index which was equaled to 1. This result implied that male inflorescence could be used as an alternative explant for commercial planting.