Interaction of larval age and antibiotic on the susceptibility of three insect species to Bacillus thuringiensis

Beegle, Clayton C.; Lewis, Leslie C.; Lynch, R. E.; Martinez, Adelaido J.

doi:10.1016/0022-2011(81)90068-9

Cited by 31 publications

(12 citation statements)

References 12 publications

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“…It is noteworthy that the antibiotic attenuation of B. thuringiensis was observed after using two antibiotics at lower concentrations than those used in similar studies (6,7), which used gentamicin, penicillin, rifampin, and streptomycin each at 500 g ml Ϫ1 of diet. It is known that dietary antibiotics can attenuate the toxicity of B. thuringiensis spore-crystal mixtures to many lepidopterans (5,16,17,19,21,25) and that such attenuation can eliminate spore synergism, leaving only the effect of Cry toxins (25,32). Therefore, it is proposed that a direct effect of residual antibiotics or an indirect effect such as an induction of a host xenobiotic detoxification response could reduce or eliminate any synergism associated with the germination of B. thuringiensis spores, leaving only the effect of Cry toxins.…”

Section: Discussionmentioning

confidence: 99%

Gut Bacteria Are Not Required for the Insecticidal Activity of Bacillus thuringiensis toward the Tobacco Hornworm, Manduca sexta

Johnston

Crickmore

2009

Appl Environ Microbiol

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It was recently proposed that gut bacteria are required for the insecticidal activity of the Bacillus thuringiensis-based insecticide, DiPel, toward the lepidopterans Manduca sexta, Pieris rapae, Vanessa cardui, and Lymantria dispar. Using a similar methodology, it was found that gut bacteria were not required for the toxicity of DiPel or Cry1Ac or for the synergism of an otherwise sublethal concentration of Cry1Ac toward M. sexta. The toxicities of DiPel and of B. thuringiensis HD73 Cry ؊ spore/Cry1Ac synergism were attenuated by continuously exposing larvae to antibiotics before bioassays. Attenuation could be eliminated by exposing larvae to antibiotics only during the first instar without altering larval sterility. Prior antibiotic exposure did not attenuate Cry1Ac toxicity. The presence of enterococci in larval guts slowed mortality resulting from DiPel exposure and halved Cry1Ac toxicity but had little effect on B. thuringiensis HD73 Cry ؊ spore/Cry1Ac synergism. B. thuringiensis Cry ؊ cells killed larvae after intrahemocoelic inoculation of M. sexta, Galleria mellonella, and Spodoptera litura and grew rapidly in plasma from M. sexta, S. litura, and Tenebrio molitor. These findings suggest that gut bacteria are not required for B. thuringiensis insecticidal activity toward M. sexta but that B. thuringiensis lethality is reduced in larvae that are continuously exposed to antibiotics before bioassay.Bacillus thuringiensis has long been regarded as a bona fide entomopathogen that can produce an array of virulence factors including insecticidal parasporal crystal (Cry) toxins, vegetative insecticidal proteins, phospholipases, immune inhibitors, and antibiotics (31). B. thuringiensis establishes lethal infections in many insect species after intrahemocoelic inoculation (9,10,14,26,31), and the insecticidal activity of Cry toxins, which lyse the intestinal epithelium, can be synergized by the presence of viable B. thuringiensis spores (31). In each instance, synergism has been attributed to hemocoelic infection by B. thuringiensis.A novel hypothesis (6, 7) proposed that B. thuringiensis is incapable of killing Lymantria dispar, Manduca sexta, Pieris rapae, or Vanessa cardui in the absence of gut bacteria. Prior exposure of L. dispar larvae to a combination of four antibiotics severely reduced the subsequent toxicity of the B. thuringiensis-based (spores and Cry toxins) bioinsecticide, DiPel (Valent BioSciences) (6). Both larval susceptibility to B. thuringiensis and the number of culturable gut bacteria were found to be negatively correlated with the concentration of antibiotics to which larvae were previously exposed. Furthermore, a total reduction in larval susceptibility was coincident with the elimination of any detectable gut bacteria. Experimental reinfection with Enterobacter sp. strain NAB3, found in the guts of some populations of L. dispar larvae, was found to rescue the toxicity of B. thuringiensis, whereas reinfection with Enterococcus casseliflavus and Staphylococcus xylosus did not. It was also sho...

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Section: Discussionmentioning

confidence: 99%

Gut Bacteria Are Not Required for the Insecticidal Activity of Bacillus thuringiensis toward the Tobacco Hornworm, Manduca sexta

Johnston

Crickmore

2009

Appl Environ Microbiol

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“…Surviving larvae were weighed after 10 or 12 days. The same batch of artificial diet was used for the duration of an experiment because our preliminary experiments, as well as work by Beegle et al (1981), indicated that activity of the Bt did not change over a 7-day period.…”

Section: Experiments With Early Instar Larvaementioning

confidence: 99%

Feeding behavior and growth of Heliothis virescens larvae on diets containing Bacillus thuringiensis formulations or endotoxins

Gould

Anderson

Landis

et al. 1991

Entomologia Exp Applicata

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Bacillus thuringiensis (Bt), spore/crystal mixtures, and purified Bt endotoxins were tested for effects on Heliothis virescens (F.) growth and behavior by use of diet‐incorporation bioassays. Larvae were exposed to three basic diet treatments: 1) feeding arenas containing only normal artificial diet, 2) feeding areas containing only a diet of B. thuringiensis formulation or endotoxin, and 3) feeding arenas where larvae could choose between normal diet and diet containing a Bt formulation or endotoxin. Young larvae avoided Bt formulations and Bt‐endotoxin‐containing diets. Even concentrations of formulations and Bt‐endotoxins that did not cause mortality or severely inhibit growth of young larvae caused avoidance. Fourth and fifth instar larvae avoided formulations and endotoxin‐containing diets when the concentrations used inhibited growth. Purified endotoxins produced by transformed E. coli cells caused avoidance similar to the spore/crystal mixture in Dipel®. Résumé Comportement alimentaire et croissance de chenilles d' Heliothis virescens sur des régimes contenant différentes doses de Bacillus thuringiensis ou des endotoxines Les effets, sur la croissance et le comportement d'Heliothis virescens F., d'endotoxines et de melanges de spores et de critaux de B. thuringiensis (Bt) ont été examinés par incorporation dans l'aliment. Les chenilles ont subi 3 types de traitements: arènes alimentaires contenant exclusivement l'aliment artificiel; arènes alimentaires avec uniquement un aliment contenant le mélange de Bt ou ses endotoxines; arènes alimentaires dans lesquelles les chenilles pouvaient choisir entre un aliment normal et un aliment contenant un mélange de Bt ou des endotoxines. Les jeunes chenilles ont évité l'aliment contenant un mélange de Bt ou des endotoxines. Même les concentrations des mélanges ou d'endotoxines qui ne sont pas mortelles ou n'inhibent pas sérieusement la croissance étaient répulsives pour les jeunes chenilles. Les chenilles de 4e et 5e stades évitaient les aliments contenant des mélanges ou des endotoxines dont les concentrations inhibent la croissance. Des endotoxines pures produites par des Escherichia coli modifies provoquent la même répulsion que le mélange spores/cristaux dans du Dipel.

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“…Kodama & Nakasuji (1971) described a situation where the presence of Streptococ cus faecalis and S. faecium in the midgut of silkworms enhances the pathogenicity of Serratia piscatorum by lowering the midgut pH to one that favors the growth of the Serratia sp. Several investigators have reported numerous factors that affect susceptibility of insects to bacterial infection, including age (Beegle et al, 1981), plant allelochemical-induced stress (Felton & Dahlman, 1984), diet (James & Lighthart, 1992), and general changes of microbiotia within insects housed in laborato ries (Lighthart, 1988). Whatever the explanation, the strain of S. marcescens tested here does kill R.pomonella, which indicates that further study is merited to understand the nature of pathogenicity associated with this strain of S. marcescens.…”

Section: Discussionmentioning

confidence: 99%

Serratia marcescens as a bacterial pathogen of Rhagoletis pomonella flies (Diptera: Tephritidae)

Lauzon¹,

Bussert²,

Sjogren³

et al. 2003

Eur. J. Entomol.

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Abstract. A nonpigmenting strain of Serratia marcescens Bizio isolated from dead and apparently diseased wild apple maggot flies, Rhagoletis pomonella (Walsh), was shown to he pathogenic to healthy apple maggot flies upon ingestion. The microorganism was detected in live adult alimentary canal organs four days post ingestion hut produced death in some flies within 24 h when flies fed on a cell concentration of 4.7 x 104 cfu/ml and within 8 h when flies fed on filter-sterilized culture medium that previously contained a 21 h culture of S. marcescens. Increasing the cell concentration 10,000 fold did not lead to an increased rate of kill. Young flies (7-10 days old) were more susceptihle to infection leading to death than were older flies (21-28 days old). The potential use of S. marcescens cells as control agents against apple maggot flies is negated hy their pathogenicity to vertehrates; however, the potential use of toxic compounds produced hy this strain of S. marcescens is discussed.

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Interaction of larval age and antibiotic on the susceptibility of three insect species to Bacillus thuringiensis

Cited by 31 publications

References 12 publications

Gut Bacteria Are Not Required for the Insecticidal Activity of Bacillus thuringiensis toward the Tobacco Hornworm, Manduca sexta

Gut Bacteria Are Not Required for the Insecticidal Activity of Bacillus thuringiensis toward the Tobacco Hornworm, Manduca sexta

Feeding behavior and growth of Heliothis virescens larvae on diets containing Bacillus thuringiensis formulations or endotoxins

Serratia marcescens as a bacterial pathogen of Rhagoletis pomonella flies (Diptera: Tephritidae)

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