SIMPLE IN VITRO CULTURE METHODS TO OBSERVE DEVELOPMENTAL STAGES AND MULTIPLICATION OF NOSEMA BOMBYCIS AND Bm NPV

Silkworm diseases are the major constraint in silk production. Silkworm diseases are caused by different types of pathogens viz. Microsporidia, Viruses, Fungi and Bacteria. These pathogens can be multiplied both in vitro and in vivo. In the present study, a simple in vitro culture method was followed to multiply Nosema bombycis in Antheraea eucalypti cell line and observed the infection and developmental stages of Nosema bombycis viz. Schizont, sporont, sporoblast and conversion of sporoblast into two types of spores having long polar tube and short polar tube. This method may also be useful to observe the developmental stages and multiplication of other microsporidia. Similarly for BmNPV multiplication also, a simple in vitro culture method was followed. BmNPV was cultured in a cell line of BmN4 and observed the infection and development of BmNPV. During initial stage of infection the cell nucleus was enlarged and granular formation was observed. Formation of small polyhedral bodies was observed at 96 h post inoculation and the nucleus was completely occupied by polyhedral bodies at 120 h post inoculation. Rupturing of the cell nucleus and release of polyhedral bodies from the cell was recorded at 144 h post inoculation. This in vitro culture method may be useful and easy in screening of anti-viral compounds against BmNPV