Insect Science 13, 19J24 Nutrient uptake in B. mori primary cultures 19 Introduction Insect cell culture has found many applications in the fields of physiology, biochemistry, genetics, develop- mental biology and insect pathology. More than 500 insect cell lines have been established from different orders (Lynn, 2001), particularly Lepidoptera, mainly due to the desire to propagate Baculoviruses as biocontrol agents. Among lepidpterous species, silkworm Bombyx mori L., in addition to being a beneficial insect, has always been the center of attention for its use as a model in biochemical and molecular studies. Using silkworm as in vivo bioreactor for production of recombinant proteins confirms this claim (Maeda et al., 1989). This could be due to its availability as a commercial insect and its unique characteristics. B. mori cell lines have been established from embryonic tissue (Inoue & Mitsuhashi, 1984; Imanishi et al., 1999; Imanishi & Ohtsuki, 1988; Pandharpande, 1994), larval and pupal ovary (Grace, 1967; Quiot, 1982) and larval midgut (Baines et al., 1994), but little success has been achieved in establishing cell lines from fat body of the silkworm, although many primary cultures have been established from B. mori s fat body (Kishimoto et al., 1999). The culture medium used for insect cells affects their propagation in primary culture and subsequently develop- ing into a cell line. Nutrition utilization and by-product Correspondence: Jalal Jalali Sendi, Department of Plant Protection, Faculty of Agriculture, University of Guilan, Rasht 41635-1314, Iran. Tel: +98 131 6690090; fax: +98 131 6690281; e-mail: jjalali2001@yahoo.com and jjalali@guilan.ac.ir Differences in nutrient uptake between the fat body and embryonic primary cultures of silkworm (Bombyx mori) LEILA MATINDOOST 1 , JALAL J. SENDI 1 , HOORIEH SOLEIMAN JAHI 2 and KAYVAN ETEBARI 3 1 Department of Plant Protection, Faculty of Agriculture, University of Guilan, Rasht, 2 Department of Virology, School of Medical Science, Tarbiat Modarres, Tehran, and 3 Department of Sericulture, Faculty of Natural Resources, University of Guilan, Somehe sara, Iran Abstract Nutrition utilization and by-product formation in cultured insect cells has been investigated in several insect cells and has been of great interest to cell culturists and physiologists. In this research the biochemical changes in embryonic and fat body primary cultures of silkworm, Bombyx mori, have been compared. TC-100 medium supplemented with 10% and 20% FBS was used in embryonic and fat body primary cultures, respectively. Medium was renewed every week and the amount of glucose, uric acid, urea, total protein and alkaline phosphatase were measured in the samples from medium of primary cultures using spectrophotometeric methods. All biochemical macromolecules except uric acid showed significant changes. Glucose decreased in embryonic tissues, while in fat body culture its amount increased. Urea accumulation in embryonic culture was higher than in the fat body cultures. Since urea is a by-product, this accumulation could be due to higher utilization of amino acids. Total protein showed considerable changes and was consumed by embryonic culture more than the fat body s. Alkaline phosphatase showed stronger activity in embryonic cells. Key words biochemical, Bombyx mori, embryo, fat body, insect cell, primary culture, silkworm DOI 10.1111/j.1744-7917.2006.00004.x www.blackwellpublishing.com/ins 19 Insect Science (2006) 13, 19J24