Morphology of a spectrum of parasporal endotoxin crystals from cultures of Bacillus thuringiensis ssp. Kurstaki isolate A3-4

• Published in: World journal of microbiology & biotechnology Vol. 17; no. 2; pp. 119 - 123
• Main Authors: FENG, Kuo-Ching, LIU, Bing-Lan, CHAN, Hsiao-Sung, TZENG, Yew-Min
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer 01.03.2001; Springer Nature B.V
• Subjects: Bacillus thuringiensis kurstaki; Bacteria; Bioassays; Biological and medical sciences; Biological control; Biotechnology; Control; Crystals; Endotoxins; Fermentation; Fundamental and applied biological sciences. Psychology; Larvae; Methods. Procedures. Technologies; Microbial engineering. Fermentation and microbial culture technology; Microbiology; Microscopy; Morphology; Phytopathology. Animal pests. Plant and forest protection; Plutella xylostella; Protozoa. Invertebrates; Toxin; Bacillus thuringiensis var. kurstaki; Bacillales; Toxicity; Morphology; Microorganism culture; Bacteria; Isolate; Parasporal body; Bacillaceae; Electron microscopy; Microbial insecticide
• ISSN: 0959-3993; 1573-0972
• DOI: 10.1023/A:1016674430979

Morphology of the parasporal δ-endotoxin crystals of Bacillus thuringiensis subsp. kurstaki isolate A3-4, a native (Taiwan) strain was studied by scanning (SEM) and transmission (TEM) electron microscopy. The typical bipyramidal crystals and an unusual parasporal inclusion with an embedded body were observed. The parasporal δ-endotoxin crystal with an embedded body, which was in different size and shape was well demonstrated in thin sections by transmission electron microscopy. The sporulated cells had multiple individually separated inclusions up to four crystals in one cell, which was unique to this isolate, and has not been reported before. The δ-endotoxin crystals included in the cell or released from the cell after batch fermentation or fed-batch fermentation did not show any altered morphological characteristics. However, judging from thin-sections of TEM, cells and the included parasporal crystals from fed-batch fermentation appeared larger than those from batch fermentation. It was observed that release of spore and parasporal crystals from the bacterial cell produced from batch cultures was earlier than that of fed-batch cultures. Preliminary bioassay results showed that the isolate cultures from both types of culture were equally effective against Plutella xylostella larvae. Based on the morphological observations, this strain may have a multiple insecticidal activities toward different insect species.[PUBLICATION ABSTRACT]