scholarly journals Identification of a NewAlcaligenes faecalisStrain MOR02 and Assessment of Its Toxicity and Pathogenicity to Insects

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Rosa Estela Quiroz-Castañeda ◽  
Ared Mendoza-Mejía ◽  
Verónica Obregón-Barboza ◽  
Fernando Martínez-Ocampo ◽  
Armando Hernández-Mendoza ◽  
...  
Keyword(s):  
Experimental Data ◽  
Galleria Mellonella ◽  
Alcaligenes Faecalis ◽  
Infection Process ◽  
Steinernema Feltiae ◽  
Phylogenomic Analysis ◽  
Phenotypic Characteristics ◽  
Host Environment ◽  
Supernatant Extract ◽  
Genome Analyses

We report the isolation of a bacterium fromGalleria mellonellalarva and its identification using genome sequencing and phylogenomic analysis. This bacterium was namedAlcaligenes faecalisstrain MOR02. Microscopic analyses revealed that the bacteria are located in the esophagus and intestine of the nematodesSteinernema feltiae, S. carpocapsae, andH. bacteriophora. UsingG. mellonellalarvae as a model, when the larvae were injected with 24,000 CFU in their hemocoel, more than 96% mortality was achieved after 24 h. Additionally, toxicity assays determined that 1 μg of supernatant extract fromA. faecalisMOR02 killed more than 70%G. mellonellalarvae 96 h after injection. A correlation of experimental data with sequence genome analyses was also performed. We discovered genes that encode proteins and enzymes that are related to pathogenicity, toxicity, and host/environment interactions that may be responsible for the observed phenotypic characteristics. Our data demonstrates that the bacteria are able to use different strategies to colonize nematodes and kill insects to their own benefit. However, there remains an extensive group of unidentified microorganisms that could be participating in the infection process. Additionally, a nematode-bacterium association could be established probably as a strategy of dispersion and colonization.

INFLUÊNCIA DO SUBSTRATO E DA LUMINOSIDADE NA INFECÇÃO DE NEMATOIDES ENTOMOPATOGÊNICOS EM Galleria mellonella (LEPIDOPTERA: PYRALIDAE)

2018 ◽  
Vol 20 (2) ◽  
pp. 91-101
Author(s):  
Andressa Lima de Brida ◽  
Silvia Renata Siciliano Wilcken ◽  
Luis Garrigós Leite
Keyword(s):  
Galleria Mellonella ◽  
Steinernema Carpocapsae ◽  
Steinernema Feltiae ◽  
Lepidoptera Pyralidae

Nematoides entomopatogênicos (NEPs) são alternativas eficientes para o controle de pragas. O emprego de novas técnicas da produção in vivo, permite o progresso da tecnologia de formulação de bioinseticidas. O objetivo do trabalho, foi avaliar a influência da luminosidade e do substrato na capacidade de infecção de juvenis infectantes (JIs) de Steinernema brazilense IBCBn 06, Steinernema carpocapsae IBCBn 02, Steinernema feltiae IBCBn 47 e Heterorhabditis amazonensis IBCBn 24 em lagartas de Galleria mellonella (Lepidoptera: Pyralidae). O delineamento experimental foi inteiramente casualizado com quatro tratamentos e oito repetições. As parcelas, constituídas por placa de Petri com, substrato-areia e substrato-papel filtro, com e sem luminosidade, inoculados com suspensão de 1,5 mL contendo 400JIs e quatro lagartas de G. mellonella. O número de JIs foi quantificado após a mortalidade das lagartas. A taxa de infecção de JIs de S. carpocapsae IBCBn 02 e S. feltiae IBCBn 47 variaram de 2,14 a 3,28 e de 11,04 a 13,09 JIs/lagarta. O substrato-areia com e sem luminosidade permitiu a maior taxa de infeção dos JIs de S. brazilense IBCBn 06 de 7,86 e 9,44 JIs/lagarta, e 13,49 JIs/lagarta com luminosidade para H. amazonensis IBCBn 24. O substrato-areia, permite a maior taxa de infecção por JIs de NEPs.

Allelopathy: a possible mechanism of suppression of plant-parasitic nematodes by entomopathogenic nematodes

Nematology ◽  
1999 ◽  
Vol 1 (7) ◽  
pp. 735-743 ◽  
Author(s):  
Parwinder S. Grewal ◽  
Edwin E. Lewis ◽  
Sudha Venkatachari
Keyword(s):  
Meloidogyne Incognita ◽  
Entomopathogenic Nematodes ◽  
Galleria Mellonella ◽  
Steinernema Feltiae ◽  
Symbiotic Bacteria ◽  
Parasitic Nematodes ◽  
Plant Parasitic Nematodes ◽  
Tomato Roots ◽  
Xenorhabdus Nematophilus ◽  
Plant Parasitic

Abstract A possible mechanism of suppression of a plant-parasitic nematode Meloidogyne incognita by entomopathogenic nematodes is described. Heat-killed entomopathogenic nematodes Steinernema feltiae and S. riobrave temporarily suppressed penetration of the root-knot nematode M. incognita into tomato roots, but live nematodes had no effect. Infective juvenile M. incognita were repelled from all entomopathogenic nematode treatments that included their symbiotic bacteria. They were repelled by Galleria mellonella cadavers infected with S. carpocapsae, S. feltiae, and S. riobrave and from cell-free culture filtrates of the symbiotic bacteria Xenorhabdus nematophilus, X. bovienii, and Xenorhabdus sp. "R" from the three nematode species, respectively. Cell-free filtrates from all three Xenorhabdus spp. were toxic to M. incognita infective juveniles causing 98-100% mortality at 15% concentration. Cell-free filtrate of Xenorhabdus sp. "R" also reduced the hatch of M. incognita eggs. Application of formulated bacterial cell-free filtrates temporarily suppressed M. incognita penetration into tomato roots in a greenhouse trial. The short-term effects of cell-free bacterial filtrates, namely toxicity and repellency, were almost entirely due to ammonium. These results demonstrate allelopathic interactions between plant-parasitic nematodes, entomopathogenic nematodes and their symbiotic bacteria. The likely role of allelopathy in the suppression of plant-parasitic nematodes by innundative applications of entomopathogenic nematodes is discussed. Allelopathie: Ein moglicher Mechanismus zur Unterdruckung pflanzenparasitarer Nematoden durch insektenpathogene Nematoden - Es wird ein moglicher Mechanismus zur Unterdruckung des pflanzenparasitaren Nematoden Meloidogyne incognita durch insektenpathogene Nematoden beschrieben. Durch Hitze abgetotete insektenpathogene Nematoden Steinernema feltiae und S. riobrave underdruckten das Eindringen des Wurzelgallenalchens M. incognita in Tomatenwurzeln, lebende Nematoden hatten keine Wirkung. Infektionsjuvenile von M. incognita wurden von allen Behandlungen mit insektenpathogenen Nematoden abgestossen, die auch die symbiontischen Bakterien einschlossen. Sie wurden durch die Kadaver von Galleria mellonella abgestossen, die mit S. carpocapsae, S. feltiae und S. riobrave infiziert waren sowie durch zellfreie Kultursubstrate der symbiontischen Bakterien Xenorhabdus nematophilus, X. bovienii und Xenorhabdus sp. "R" aus den drei genannten Nematodenarten. Zellfreie Kultursubstrate von allen drei Xenorhabdus spp. waren giftig fur die Infektionsjuvenilen von M. incognita und verursachten in einer Konzentration von 15% Abtotungsraten von 98-100%. Zellfreie Kultursubstrate von Xenorhabdus sp. "R" vermiderten ausserdem das Schlupfen von M. incognita-Eiern. In einem Gewachshausversuch unterdruckten formulierte zellfreie Bakterienfiltrate vorubergehend das Eindringen von M. incognita in Tomatenwurzeln. Die Kurzzeitwirkungen von zellfreien Bakterien filtraten, namentlich Giftigkeit und Abstossung, waren nahezu ganz bedingt durch Ammoniak. Diese Ergebnisse zeigen das Vorhandensein von allelopathischen Wechselwirkungen zwischen pflanzenparasitaren Nematoden, insektenpathogenen Nematoden und deren symbiontischen Bakterien. Die wahrscheinliche Rolle von Allelopathie bei der Unterdruckung pflanzenparasitarer Nematoden durch eine Massenanwendung insektenpathogener Nematoden wird diskutiert.

Infectivity of populations of the entomopathogenic nematodes Steinernema feltiae and Heterorhabditis megidis in relation to temperature, age and lipid content

Nematology ◽  
2000 ◽  
Vol 2 (5) ◽  
pp. 515-521 ◽  
Author(s):  
Hara Menti ◽  
Denis Wright ◽  
Roland Perry
Keyword(s):  
Lipid Content ◽  
Dose Response ◽  
Entomopathogenic Nematodes ◽  
Galleria Mellonella ◽  
Steinernema Feltiae ◽  
Optimal Temperature ◽  
Temperature Range ◽  
Heterorhabditis Megidis ◽  
Before And After ◽  
The Uk

AbstractThe infectivity of populations of the entomopathogenic nematodes Steinernema feltiae and Heterorhabditis megidis from Greece (GR) and the UK was compared using Galleria mellonella larvae as hosts. Dose-response tests showed that the two Steinernema populations did not differ in their establishment rates but they were more infective than H. megidis UK 211. The temperature range for infectivity was greater than that for development. However, the optimal temperature for infection and development for all populations was 23°C. Infectivity of Steinernema populations was not affected by storage for 12 weeks. However, 12 week-old H. megidis UK 211 infective juveniles (IJ) were less infective than fresh IJ. H. megidis GR showed very low establishment rates at all the doses and temperatures tested, before and after storage. The results are discussed in relation to the nematodes' climatic origin and lipid content. Pouvoir infestant de populations des nématodes entomopathogènes Steinernema feltiae et Heterorhabditis megidis suivant la température, l'âge et le contenu lipidique - Le pouvoir infestant de populations des nématodes entomopathogènes Steinernema feltiae et Heterorhabditis megidis provenant de Grèce et du Royaume Uni a été comparée, utilisant comme hôte Galleria mellonella. Les tests de dose/réaction ont montré que les taux d'établissement des deux populations ne diffèrent pas mais que leur pouvoir infestant était plus élevée que celle de H. megidis UK211. La plage des températures permettant l'infestation était plus étendue que celle relative au développement. Cependant, les températures optimales pour l'infestation et pour le développement étaient l'une et l'autre de 23°C pour toutes les populations. L'infestivité des populations de Steinernema n'a pas été affectée par un stockage de 12 semaines. Les juvéniles infestants de H. megidis UK211 âgés de 12 semaines montraient toutefois une infestivité plus faible que celle d'individus frais. Les specimens de H. megidis provenant de Grèce présentaient - que ce soit avant ou après le stockage - des taux d'établissement très faibles pour toutes les doses et les températures testées. Ces résultats sont discutés en relation avec l'origine climatique et le contenu lipidique des nématodes.

Scavenging or infection? Possible host choosing by entomopathogenic nematodes

Nematology ◽  
2008 ◽  
Vol 10 (2) ◽  
pp. 251-259 ◽  
Author(s):  
Ernesto San-Blas ◽  
Barbara Pembroke ◽  
Simon Gowen
Keyword(s):  
Entomopathogenic Nematodes ◽  
Galleria Mellonella ◽  
Nematode Species ◽  
Foraging Strategy ◽  
Steinernema Feltiae ◽  
Natural Field ◽  
Heterorhabditis Megidis ◽  
The Dead

AbstractEntomopathogenic nematodes are able to survive by scavenging. We tested Steinernema feltiae, S. affine and Heterorhabditis megidis alone or in different combinations to evaluate the responses of these nematodes when dead or live Galleria mellonella larvae were offered. Steinernema feltiae and S. affine scavenged upon dead G. mellonella larvae and about 30% more dead larvae were penetrated than live ones. By contrast, H. megidis penetrated more live larvae than dead ones. When the nematode species were combined, the results varied among the combinations, but the dead larvae were always used as a host. The behaviour of natural field populations of S. feltiae and S. affine was also compared. Steinernema feltiae showed no difference between scavenging and performing 'normal infections', whereas S. affine scavenged to a reduced amount (around 60% less); this difference could be related to the particular foraging strategy of these nematodes.

Sex and the dynamics of infection in the entomopathogenic nematode Steinernema feltiae

1997 ◽  
Vol 71 (3) ◽  
pp. 197-202 ◽  
Author(s):  
D.A. Bohan ◽  
W.M. Hominick
Keyword(s):  
Sex Ratio ◽  
Entomopathogenic Nematodes ◽  
Galleria Mellonella ◽  
Entomopathogenic Nematode ◽  
Steinernema Feltiae ◽  
Infective Juvenile ◽  
Infective Stage ◽  
Male And Female ◽  
Per Capita ◽  
Infection Interaction

AbstractAn infection experiment was conducted to assess the change in the proportions of Steinernema feltiae Filipjev (Site 76 strain) infective juveniles becoming male or female on exposure to the test host Galleria mellonella L. Using a mathematical model for the infection interaction, the per capita probability of penetration per unit time (transmission coefficient), for those juveniles becoming male or female, and the magnitude of the male and female classes in the infective juvenile pool were estimated. The results show that S. feltiae infective juveniles which subsequently become female have a greater probability of invasion into test hosts than their male counterparts, which leads to markedly female biased sex ratios during the initial stages of the infection interaction. As the infection progresses, however, it was found that the sex ratio became balanced. This was because the underlying sex ratio in the infective stage pool was balanced. The implications of this dynamism in the sex ratio of the entomopathogenic nematodes are discussed with respect to the infection interaction, transmission and the likely environment in which the infective juveniles reside.

scholarly journals Intraspecific variation among isolates of the entomopathogenic nematode Steinernema feltiae from Bull Island, Ireland

Nematology ◽  
2009 ◽  
Vol 11 (3) ◽  
pp. 439-451 ◽  
Author(s):  
Martin Downes ◽  
Conor Meade ◽  
Stephen Boyle ◽  
Alec Rolston ◽  
Thomae Kakouli-Duarte
Keyword(s):  
Intraspecific Variation ◽  
Galleria Mellonella ◽  
Insect Pests ◽  
Entomopathogenic Nematode ◽  
Laboratory Culture ◽  
Steinernema Feltiae ◽  
Host Insect ◽  
Large Numbers ◽  
Insect Mortality ◽  
Control Insect

AbstractThe application of large numbers of entomopathogenic nematodes (EPN) to control insect pests of agriculture is likely to have an impact on the local EPN fauna, yet little is known about the intraspecific relationships between EPN populations, particularly with regard to phylogeny and outbreeding. Here we assess the fitness, with regards to fecundity, host insect mortality and time taken to produce progeny, of isolates of Steinernema feltiae from Bull Island, Ireland. Exon-primed, intron-crossing (EPIC) PCR was used to examine intraspecific phylogenies between S. feltiae isolates, and identified up to three possible colonisation events of Bull Island. EPIC-PCR grouped two isolates, 33.D.(2) and 59.F.(2), separately from the remaining ten S. feltiae isolates These same two isolates consistently performed poorly in all fitness assessments. Following the crossbreeding of all isolates in Galleria mellonella, the number of host cadavers exhibiting emerging infective juveniles was significantly fewer than expected and there were significant differences between isolates in the number of days until progeny were observed. Host insect mortality varied between 40 and 87%. Such intraspecific variation may be a result of adaptation to different microhabitats of Bull Island, which in turn may be accentuated by laboratory culture practices.

Effect of recycling temperature on the infectivity of entomopathogenic nematodes

1997 ◽  
Vol 75 (12) ◽  
pp. 2137-2141 ◽  
Author(s):  
Ganpat B. Jagdale ◽  
Roger Gordon
Keyword(s):  
Entomopathogenic Nematodes ◽  
Galleria Mellonella ◽  
Steinernema Carpocapsae ◽  
Steinernema Feltiae ◽  
Wax Moth

Four strains of entomopathogenic nematodes were recycled in vivo for 2 years at temperatures ranging from 10 to 25 °C, then the infectivity of their infective juveniles was compared. Infectivity was examined by measuring LC50 values for wax moth (Galleria mellonella) larvae at bioassay temperatures ranging from 5 to 25 °C. Of the four strains examined, only the Umeå and NF strains of Steinernema feltiae that had been recycled at 10 °C infected and killed the insects at a bioassay temperature of 5 °C. The Steinernema carpocapsae All and Steinernema riobravis TX strains were infective at 10 °C only when the recycling temperature was ≤ 20 °C. The infectivity of the two strains of S. feltiae at 10 or 15 °C was compromised by propagating them at higher temperatures (20–25 °C). The Umeå strain of S. feltiae displayed an impaired capacity to infect hosts at higher temperatures (20–25 °C) when recycled at lower (≤ 15 °C) temperatures. The capacity of these nematodes to adjust to different recycling temperatures is discussed in relation to their infectivity in different field situations.

The integrated use of chemical insecticides and the entomopathogenic nematode, Steinernema feltiae, for the control of sweetpotato whitefly, Bemisia tabaci

Nematology ◽  
2003 ◽  
Vol 5 (5) ◽  
pp. 713-720 ◽  
Author(s):  
Andrew Cuthbertson ◽  
Justine Head ◽  
Keith Walters ◽  
Alistair Murray
Keyword(s):  
Bemisia Tabaci ◽  
Host Plants ◽  
Galleria Mellonella ◽  
Entomopathogenic Nematode ◽  
Steinernema Feltiae ◽  
Sweetpotato Whitefly ◽  
Chemical Agents ◽  
Direct Exposure ◽  
Systemic Pesticide ◽  
The Impact

AbstractThe integration of infective juveniles of the entomopathogenic nematode, Steinernema feltiae, with chemical insecticides to control second instar stages of the sweetpotato whitefly, Bemisia tabaci, was investigated. The effects of direct exposure for 24 h to field rate dilutions of four insecticides (imidacloprid, buprofezin, teflubenzuron and nicotine) on nematode infectivity to Galleria mellonella larvae were tested in a sand tube bioassay. Teflubenzuron had the least adverse effect on the nematodes whilst imidacloprid, buprofezin and nicotine significantly reduced nematode infectivity. The impact of dry insecticide residue present on tomato and verbena foliage on nematode infectivity against B. tabaci larvae was investigated for buprofezin, teflubenzuron and nicotine (imidacloprid is a systemic pesticide and no residues would occur on foliage). No significant reduction on the level of control of B. tabaci was recorded when compared with the infectivity of nematodes applied to residue-free foliage of either tomato or verbena plants. Nematodes in combination with imidacloprid gave significantly higher B. tabaci larvae mortality compared to either treatment individually on both host plants. The integration of S. feltiae and these chemical agents into an integrated pest management programme for the control of B. tabaci is discussed.

scholarly journals A Bacillus thuringiensis Chitin-Binding Protein is Involved in Insect Peritrophic Matrix Adhesion and Takes Part in the Infection Process

Toxins ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 252
Author(s):  
Jiaxin Qin ◽  
Zongxing Tong ◽  
Yiling Zhan ◽  
Christophe Buisson ◽  
Fuping Song ◽  
...  
Keyword(s):  
Bacillus Thuringiensis ◽  
Galleria Mellonella ◽  
Binding Protein ◽  
Insect Pest ◽  
Infection Process ◽  
Peritrophic Matrix ◽  
Limited Information ◽  
Chitin Binding Protein

Bacillus thuringiensis (Bt) is used for insect pest control, and its larvicidal activity is primarily attributed to Cry toxins. Other factors participate in infection, and limited information is available regarding factors acting on the peritrophic matrix (PM). This study aimed to investigate the role of a Bt chitin-binding protein (CBPA) that had been previously shown to be expressed at pH 9 in vitro and could therefore be expressed in the alkaline gut of lepidopteron larvae. A ∆cbpA mutant was generated that was 10-fold less virulent than wild-type Bt HD73 towards Ostrinia furnacalis neonate larvae, indicating its important role in infection. Purified recombinant Escherichia coli CBPA was shown to have a chitin affinity, thus indicating a possible interaction with the chitin-rich PM. A translational GFP–CBPA fusion elucidated the localization of CBPA on the bacterial surface, and the transcriptional activity of the promoter PcbpA was immediately induced and confirmed at pH 9. Next, in order to connect surface expression and possible in vivo gut activity, last instar Galleria mellonella (Gm) larvae (not susceptible to Bt HD-73) were used as a model to follow CBPA in gut expression, bacterial transit, and PM adhesion. CBPA-GFP was quickly expressed in the Gm gut lumen, and more Bt HD73 strain bacteria adhered to the PM than those of the ∆cbpA mutant strain. Therefore, CBPA may help to retain the bacteria, via the PM binding, close to the gut surface and thus takes part in the early steps of Bt gut interactions.

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