Crystal Morphology of Local Bacillus thuringiensis SY56.3 Isolate

Abstract

Bacillus thuringiensis (Bt) is an aerobic, Gram (+) and spore-forming entomopathogenic bacterium belonging to Bacillus cereus group together with Bacillus anthracis. Bt is the most widely and effectively used biological control agent against insect pests throughout the world. Following morphological and molecular characterization of the Bt SY56.3 isolate, Scanning Electron Microscopy (SEM) analysis was performed to determine the morphology of spore and parasporal crystal proteins (Cry) in this study. A small amount of lyophilized spore-crystalline mixture of Bt SY56.3 was put on a microscope slide containing a drop of distilled water and homogenized thoroughly. Then, it was dried at room temperature while quickly passing the slide 20 times over burner flame. The slide was then fixed onto the electron microscope holder with the aid of SC7620 Mini-Sputter Coater device. The slide was made conductive by coating with Golden Poladium (Au/Pd) for 30 seconds. The samples containing the Cry proteins in the range of 25-130 kDa were then placed in scanning electron microscope (LEO440) and visualized at 20kV. The size of crystal proteins ranged between 0.3-2 μm. It was observed that Bt SY56.3 isolate had cubic, bipyramidal, circular and irregular shaped Cry proteins. Present findings revealed that Bt SY56.3 could be used for biotechnological control applications because of different functions of these different Cry proteins.

Keywords

• Bacillus thuringiensis
• Cry protein
• Bioinsecticide
• Bt

Project Number

FBD-08-540.

Yerel Bacillus thuringiensis SY56.3 izolatının kristal morfolojisi

Abstract

Bacillus thuringiensis (Bt), Bacillus cereus grubuna ait, aerobik, Gram (+) ve spor oluşturan bir entomopatojenik bakteridir. Bt, dünya çapında böcek zararlılarına karşı en yaygın ve etkili kullanılan biyolojik kontrol ajanıdır. Bu çalışmada, Bt SY56.3 izolatının morfolojik ve moleküler karakterizasyonunun ardından, spor ve parasporal kristal proteinlerinin (Cry) morfolojisini belirlemek için Taramalı Elektron Mikroskobu (SEM) analizi yapılmıştır. Az miktarda liyofilize edilmiş Bt SY56.3 spor-kristal karışımı, bir damla saf su içeren bir mikroskop lamına konulmuş ve iyice homojenize edilmiştir. Daha sonra, lam, oda sıcaklığında 20 kez hızlıca bek alevi üzerinden geçirilerek kurutulmuştur. Ardından, lam, SC7620 Mini-Sputter Coater cihazı yardımıyla elektron mikroskobu tutucusuna sabitlenmiştir. Lam, 30 saniye boyunca Altın Poladyum (Au/Pd) ile kaplanarak iletken hale getirilmiştir. 25-130 kDa aralığında Cry proteinleri içeren örnekler daha sonra taramalı elektron mikroskobuna (LEO440) yerleştirilmiş ve 20 kV'de görüntülenmiştir. Kristal proteinlerin boyutu 0,3-2 μm arasında gözlenmiştir. Bt SY56.3 izolatının kübik, bipiramidal, dairesel ve düzensiz şekilli Cry proteinlerine sahip olduğu gözlemlenmiştir. Mevcut bulgular, bu farklı Cry proteinlerinin farklı işlevleri nedeniyle Bt SY56.3'ün biyoteknolojik kontrol uygulamalarında kullanılabileceğini ortaya koymaktadır.

Keywords

• Bacillus thuringiensi
• Bt
• Cry protein
• Biyoinsektisit

Project Number

FBD-08-540.

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