Synergistic activity of a Bacillus thuringiensis delta-endotoxin and a bacterial endochitinase against Spodoptera littoralis larvae

Regev, Avital; Keller, Menachem; Strizhov, N.; Sneh, B.; Prudovsky, Evgenia; Chet, I.; Ginzberg, Idit; Koncz-Kálmán, Zsuzsanna; Koncz, Csaba; Schell, Jeff; Zilberstein, Aviah

doi:10.1128/aem.62.10.3581-3586.1996

Cited by 202 publications

(84 citation statements)

References 54 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Interestingly, the chitinase-producing B. thuringiensis or its related species B. cereus strains can enhance the insecticidal toxicity of active B. thuringiensis strains (Morris 1976;Sneh et al 1983). This finding might be applied for the development of new B. thuringiensis formulations (Tabashnik 1992;Regev et al 1996;Sampson and Gooday 1998;Wiwat et al 2000). Several reports have described selection and characterization of chitinolytic B. thuringiensis strains (Barboza-Corona et al 1999;Rojas-Avelizapa et al 1999).…”

Section: Introductionmentioning

confidence: 85%

“…Subsequently destruction of the transmembrane potential and the osmotic lysis of cells lining the midgut cause the death of the larvae (Gill et al 1992;Aronson and Shai 2001). Some reports revealed that chitinase could enhance this process and might be used to improve the pesticidal activity of B. thuringiensis (Regev et al 1996;Sampson and Gooday 1998;Wiwat et al 2000).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Chitinolytic activities in Bacillus thuringiensis and their synergistic effects on larvicidal activity

et al. 2002

View full text Add to dashboard Cite

Aims: To investigate the distribution of chitinase in Bacillus thuringiensis strains, and the enhancing effects of the chitinase-producing B. thuringiensis strains on insecticidal toxicity of active B. thuringiensis strain against Spodoptera exigua larvae. Methods and Results: The chitinolytic activities of B.thuringiensis strains representing the 70 serotypes were investigated by the whitish opaque halo and the colorimetric method. Thirtyeight strains produced different levels of chitinase at pH 7AE0, and so did 17 strains at pH 10AE0. The strain T04A001 exhibited the highest production, reaching a specific activity of 355 U ml )1 in liquid medium. SDS-PAGE and Western blotting showed that the chitinase produced by some B. thuringiensis strains had a molecular weight of about 61 kDa. The bioassay results indicated that the chitinase-producing B. thuringiensis strains could enhance the insecticidal activity of B. thuringiensis strain DL5789 against S. exigua larvae, with an enhancing ratio of 2AE35-fold. Conclusion: This study demonstrated that chitinase was widely produced in B. thuringiensis strains and some of the strains could enhance the toxicity of active B. thuringiensis strain. Significance and Impact of the Study: This is the first investigation devoted exclusively to analyse the distribution of chitinase in B. thuringiensis. It infers that the chitinase produced by B. thuringiensis might play a role in the activity of the biopesticide. INTRODUCTIONChitin, the b-(1,4)-linked homopolysaccharide of N-acetylglucosamine, is the second most abundant polysaccharide in nature. It occurs in insects as a major component of the cuticle and of the peritrophic membrane, a protective sleeve lining the gut of many insects (Kramer and Koga 1986;Cabib 1987). Chitinase, which is defined as an enzyme (EC 3.2.1.14) with a specific hydrolytic activity directed against the homopolymer chitin, might play a key role in virulence of some pathogens that infect insects via the peritrophic membrane. Enzymatic cleavage occurs randomly at internal locations over the entire length of the chitin microfibril, leading to the impairment of the insect midgut (Kramer and Koga 1986;Hawtin et al. 1997;Kramer et al. 1997). Hypothetically, chitinase causes perforations in the gut peritrophic membrane, which facilitate entry of the pathogens into the haemocoel of susceptible insects (Brandt et al. 1978).The Gram-positive bacterium Bacillus thuringiensis is an important industrial organism and is used worldwide for pest control in agriculture, horticulture and silviculture, as well as for the control of disease-related insect vectors. Its specific activities against a variety of insects are attributed to the parasporal crystals, which are produced and assembled during sporulation. After ingestion by target insects (usually the larvae), the crystals are solubilized and converted into active toxins by proteases in the larval midgut. The active toxins bind to specific receptors on the surfaces of the midgut epithelium cells, and insert into the me...

show abstract

Section: Introductionmentioning

confidence: 85%

Section: Introductionmentioning

confidence: 99%

Chitinolytic activities in Bacillus thuringiensis and their synergistic effects on larvicidal activity

et al. 2002

View full text Add to dashboard Cite

show abstract

“…It is long since known that chitinase activities resulting in the degradation of the PM play key roles in the virulence of entomopathogens that are transmitted orally and infect insects via the midgut that is normally shielded by the PM. One known mechanism is that toxins can more easily act on the epithelial cells if they are no longer protected by the PM (Sneh et al, 1983;Regev et al, 1996;Sampson and Gooday, 1998;Ramirez-Suero et al, 2011;Bahar et al, 2012). We recently found genetic evidence for the presence of toxin genes in the genome of P. larvae (Fünfhaus et al, 2009).…”

Section: Paenibacillus Larvae Degrades the Pm In Infected Larvaementioning

confidence: 99%

Honey bee larval peritrophic matrix degradation during infection with Paenibacillus larvae, the aetiological agent of American foulbrood of honey bees, is a key step in pathogenesis

Garcia‐Gonzalez

Genersch

2013

Environmental Microbiology

View full text Add to dashboard Cite

Paenibacillus larvae, the aetiological agent of American foulbrood (AFB) of honey bees, causes a fatal intestinal infection in larvae and invades the haemocoel by breaching the midgut. The peritrophic matrix lining the midgut epithelium in insects constitutes an effective barrier against abrasive food particles, xenobiotics, toxins and pathogens. Pathogens like P. larvae entering the host through the gut first need to overcome this barrier. To better understand AFB pathogenesis, we analysed the fate of the peritrophic matrix in honey bee larvae during P. larvae infection. Using histochemical techniques, we first established that chitin is a major component of the honey bee larval peritrophic matrix. Rearing larvae on a diet containing a fluorochrome blocking formation of the peritrophic matrix or a bacterial endochitinase revealed that a fully formed peritrophic matrix is essential for larval survival. Larvae infected by P. larvae showed total degradation of the peritrophic matrix enabling the bacteria to directly attack the epithelial cells. Carbon source utilization tests confirmed that P. larvae is able to metabolize colloidal chitin. We propose that P. larvae degrades the peritrophic matrix to allow direct access of the bacteria or of bacterial toxins to the epithelium to prepare the breakthrough of the epithelial layer.

show abstract

“…This perforation may provide an access for TMOF to be delivered into the gut cells and initiates its sequential effects. Previous results obtained by Regev et al (1996) indicated that pore formation of the peritrophic matrix, caused by chitinase, enhanced the CryIC toxicity towards S. littoralis.…”

Section: Discussionmentioning

confidence: 87%

Synergistic activity of Bacillus thuringiensis δ‐endotoxin and TMOF against Culex pipiens and Spodoptera littoralis larvae

Mohammed

Diab

Khalil

2017

Entomological Research

View full text Add to dashboard Cite

Trypsin Modulating Oostatic Factor (TMOF) is a decapeptide hormone that inhibits the biosynthesis of digestive enzymes in the mosquito midgut. The hormone inhibits food digestion and ultimately leads to starvation and death. It has been used as a biological insecticide to control mosquitoes. In an attempt to increase the insecticidal activity of TMOF, a combination of CryIC (δ‐endotoxin from Bacillus thuringiensis) and TMOF was determined. Eight recombinant proteins fused with GST (glutathione‐S‐transferase) were expressed in Escherichia coli cells. Their insecticidal activities were determined against Culex pipiens and Spodoptera littoralis larvae. Purified GST‐TMOF and its analogue GST‐YDPAS exhibited a moderate toxicity on C. pipiens larvae with LC50 of 145.9 and 339.9 μg/mL, respectively. Unexpectedly, no mortality was observed in first instar larvae of S. littoralis. Puirified GST‐TMOF and GST‐YDPAS together with Bt toxin showed a synergistic toxic effect on both Culex and Spodoptera larvae. In the presence of 100 μg/mL GST‐TMOF and GST‐YDPAS, the median lethal concentration of entomocidus on culex larvae decreased from 52.1 to 16.7 and 31.9 μg/mL, respectively. Likewise, GST‐TMOF and GST‐YDPAS incorporated with 0.07 μg/cm2 of enotmocidus showed insecticidal activity against S. littoralis with LC50 of 16.4 and 21.9 μg/cm2. The E. coli lysates containing GST‐CryIC and its 3′‐truncated version showed low toxicity against the lepidopteran insect (10.8 and 16.6 μg/cm2) compared to 0.15 μg/cm2 of the native crystalline form of CryIC. Similarly, the mosquitocidal activity of the recombinant Bt toxins was low.

show abstract

Synergistic activity of a Bacillus thuringiensis delta-endotoxin and a bacterial endochitinase against Spodoptera littoralis larvae

Cited by 202 publications

References 54 publications

Chitinolytic activities in Bacillus thuringiensis and their synergistic effects on larvicidal activity

Chitinolytic activities in Bacillus thuringiensis and their synergistic effects on larvicidal activity

Honey bee larval peritrophic matrix degradation during infection with Paenibacillus larvae, the aetiological agent of American foulbrood of honey bees, is a key step in pathogenesis

Synergistic activity of Bacillus thuringiensis δ‐endotoxin and TMOF against Culex pipiens and Spodoptera littoralis larvae

Contact Info

Product

Resources

About