ABSTRACT
Two novel mosquitocidal bacteria, VB17 and VB24, identified as new Bacillus species were isolated from dead mosquito larvae obtained in Florida aquatic habitats. Gas chromatographic analysis of fatty acid methyl esters (GC-FAME) and 16S rRNA sequencing indicated that VB24 is closely related to Bacillus sphaericus whereas VB17 does not have a close relationship with either Bacillus thuringiensis or B. sphaericus. Both isolates were significantly more active than B. sphaericus 2362 against Aedes taeniorhynchus, Anopheles quadrimaculatus, Culex quinquefasciatus larvae, and as active as B. sphaericus 2362 against Anopheles gambiae. Interestingly, however, both were not active against Aedes aegypti larvae, indicating some level of insecticidal specificity.
Subject(s)
Bacillus/isolation & purification , Culicidae/parasitology , Mosquito Control/methods , Pest Control, Biological/methods , Animals , Bacillus/genetics , Bacterial Proteins/genetics , DNA, Bacterial/analysis , DNA, Bacterial/isolation & purification , Microscopy, Electron, TransmissionABSTRACT
Mosquitocidal bacteria, M413 and C32 have been isolated from sediment samples collected from woodland and ditch, respectively. Gas chromatographic analysis of fatty acids methyl esters (GC-FAME) and 16S rRNA gene sequence alignment results showed these isolates belong to Bacillus cereus. The SDS-PAGE analysis of sporulated cultures of both isolates showed two major bands very similar in size. Interestingly, however, M413 is mainly toxic to 4th instars of Ochlerotatus taeniorhynchus whereas C32 is to those of Culex quinquefasciatus.
Subject(s)
Bacillus cereus/isolation & purification , Culicidae/drug effects , Endotoxins/toxicity , Animals , Bacillus cereus/chemistry , Bacillus cereus/physiology , Base Sequence , Chromatography, Gas , Culicidae/growth & development , Electrophoresis, Polyacrylamide Gel , Endotoxins/chemistry , Geologic Sediments/microbiology , Larva/drug effects , Larva/growth & development , Lethal Dose 50 , Pest Control, Biological , RNA, Bacterial/chemistry , RNA, Ribosomal/chemistry , Sequence Alignment , Sequence Analysis, RNAABSTRACT
A Bacillus sphaericus highly toxic to 4th-stage Culex quinquefasciatus was isolated from sediment samples collected at Winter Beach marsh in Indian River County, Florida. This isolate, named WBM 1-1-13, showed significantly higher toxicity compared with strain 2297. WBM 1-1-13 is equivalent, though better initially, to the toxicity of strain 2362, the active ingredient of VectoLex. Furthermore, the Winter Beach marsh isolate produced more Bin per unit medium than strain 2362, which suggests that this new isolate could be useful for Culex control.
