Phenotypic characterization of the Xenorhabdus bacterial symbiont of a Texas strain of the entomopathogenic nematode Steinernema riobrave, and characterization of the Xenorhabdus bovienii bacterial symbiont of a Newfoundland strain of Steinernema feltiae

2000 ◽  
Vol 46 (7) ◽  
pp. 618-622 ◽  
Author(s):  
Hongjun He ◽  
Roger Gordon ◽  
John A Gow
Keyword(s):  
Entomopathogenic Nematodes ◽  
Entomopathogenic Nematode ◽  
Bacterial Symbiont ◽  
The Other ◽  
Steinernema Feltiae ◽  
Phenotypic Characterization ◽  
Bacterial Symbionts ◽  
European Origin ◽  
Low Concentrations

Two bacterial symbionts of entomopathogenic nematodes, one of which originated from Texas, U.S.A., and the other from Newfoundland, Canada, were characterized phenotypically. These strains belonged to the genus Xenorhabdus. The Newfoundland (NF) strain was shown to be X. bovienii but the Texas (TX) strain was not identified at the species level. Four additional cultures of Xenorhabdus were included in the study. These were a strain of X. bovienii (Umeå), which was from a nematode of European origin, and strains of X. nematophilus, X.beddingii, and X.poinarii. The tests used in this study indicated identical properties for the NF (North American) and Umeå (European) strains of X. bovienii. These could be differentiated from the other strains studied by their failure to grow at 34°C and resistance to low concentrations of a mixture of amoxilline and clavulanic acid. The Xenorhabdus TX strain could be differentiated from the other strains studied by its failure to grow at 10°C. Of the tests done, approximately 30 were useful in distinguishing between the strains and species studied.Key words: symbionts, nematode, Steinernema, Xenorhabdus, Xenorhabdus bovienii.

scholarly journals Characterization Physiology and Molecular Bacteria Symbiont- Entomopathogenic Nematodes based of Gene Sequences Encoding the 16S rRNA District of Bromo Probolinggo

2017 ◽  
Vol 18 (1) ◽  
pp. 39
Author(s):  
Bagus Setiawan ◽  
Didik Sulistyanto ◽  
Kartika Senjarini
Keyword(s):  
16S Rrna ◽  
Entomopathogenic Nematodes ◽  
Phenotypic Characterization ◽  
Bacterial Symbionts ◽  
Rrna Sequence ◽  
16S Rrna Sequence ◽  
Gene Encoding ◽  
Bacillus Strain ◽  
Rrna Sequences

This study aims to identify entomopathogenic nematodes symbiotic bacteria phenotypically and based on the gene encoding 16S rRNA sequences. Bacterial symbionts of entomopathogenic nematodes, obtained from isolates from the area Wonokerto (WN01) and isolates Sukapura (SP01), Bromo, Probolinggo, two symbiont bacteria was found in entomopathogenic nematodes Steinernema sp. The method used in this study are: the isolation of entomopathogenic nematodes Steinernema sp. and bacterial symbionts conventionally for the identification of phenotypically, after the characterization of bacterial isolates, the isolation of genomic DNA, 16S rRNA PCR, DNA purification and DNA sequence analysis. The results based on phenotypic characterization showed that isolates WN01 and SP01, yellowish white, gram positive, negative bioluminenscene, catalase positive, can not hydrolyze urea, and also can not produce H2S. The results of the gene encoding 16S rRNA sequence can be deduced WN01 isolates have in common with the bacteria Bacillus strain toyonensis BCT 7112, while the SP01 isolates have in common with the bacteria Bacillus strain cereus ATCC 14 579.

scholarly journals Genotypic and Phenotypic Characterization of Treponema phagedenis from Bovine Digital Dermatitis

2020 ◽  
Vol 8 (10) ◽  
pp. 1520
Author(s):  
Hector M. Espiritu ◽  
Lovelia L. Mamuad ◽  
Su-jeong Jin ◽  
Seon-ho Kim ◽  
Seok-won Kwon ◽  
...  
Keyword(s):  
Slow Growth ◽  
Small Difference ◽  
Phenotypic Characterization ◽  
Average Nucleotide Identity ◽  
Digital Dermatitis ◽  
16S Rrna Analysis ◽  
Single Strain ◽  
Low Concentrations ◽  
Bovine Strain

This study aimed to isolate and characterize Treponema spp. from bovine digital dermatitis (BDD)-infected dairy cattle. Seven isolates were characterized in this study. Isolates exhibited slow growth, and colonies penetrated the agar and exhibited weak β-hemolysis. Round bodies were observed in old and antibiotic-treated cultures. Cells ranged from 9–12 µm in length, 0.2–2.5 µm in width, and were moderately spiraled. The 16S rRNA analysis revealed the isolates as Treponema phagedenis with >99% sequence homology. Isolates had alkaline phosphatase, acid phosphatase, β-galactosidase, N-acetyl-β-glucosaminidase, esterase (C4), esterase lipase (C8), naphthol-AS-BI-phosphohydrolase, and β-glucuronidase activities. Low concentrations of ampicillin, erythromycin, and tetracycline were required to inhibit the growth of isolates. Formic, acetic, and butyric acids were produced, while propionic acid was significantly utilized, indicating its essentiality for treponemal growth. The isolates shared the same characteristics and, therefore, were considered as a single strain. Isolate HNL4 was deposited as a representative isolate (Treponema phagedenis KS1). The average nucleotide identity of strain KS1 showed a small difference with the human strain (99.14%) compared with bovine strain (99.72%). This study was the first to isolate and characterize Treponema phagedenis from BDD in Korea and, hence, it delivered pathogenicity-related insights and provided valuable information that can be used for the management of BDD.

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.

PHENOTYPIC CHARACTERIZATION OF BENECKEA PARAHAEMOLYTICA: A PRELIMINARY REPORT1

1973 ◽  
Vol 36 (4) ◽  
pp. 214-219 ◽  
Author(s):  
Paul Baumann ◽  
Linda Baumann
Keyword(s):  
Liquid Medium ◽  
Type Strain ◽  
Solid Medium ◽  
Morphological Characterization ◽  
The Other ◽  
Polar Flagellum ◽  
Phenotypic Characterization ◽  
Phenotypic Traits ◽  
General Properties

Eighty-six strains which were isolated from cases of gastroenteritis and had the general properties of the genus Beneckea were submitted to an extensive nutritional, physiological, and morphological characterization. The results indicated that this collection of strains, which included the type strain of Beneckea parahaemolytica, was phenotypically homogeneous and distinguishable from the other known species of Beneckea by multiple, unrelated, phenotypic traits. When grown in liquid medium, strains of B. parahaemolytica had single, sheathed, polar flagella; when grown on solid medium, these strains had unsheathed, peritrichous flagella in addition to the sheathed, polar flagellum. Additional traits of use for differentiation of this species from the remaining species of the genus Beneckea were the ability of B. parahaemolytica to grow at 40 C, utilize d-galactose, l-leucine, l-histidine, and putrescine and the inability to utilize sucrose, dl-β-hydroxy-butyrate or give a positive Voges-Proskauer reaction. The validity of some of the traits previously used to identify B. parahaemolytica as well as the possible difficulties encountered in the identification of this organism from marine sources are considered.

scholarly journals Host-Specific Activation of Entomopathogenic Nematode Infective Juveniles

Insects ◽  
2018 ◽  
Vol 9 (2) ◽  
pp. 59 ◽  
Author(s):  
Valentina Alonso ◽  
Shyon Nasrolahi ◽  
Adler Dillman
Keyword(s):  
Entomopathogenic Nematodes ◽  
Morphological Changes ◽  
Entomopathogenic Nematode ◽  
Infection Process ◽  
Bacterial Symbiont ◽  
Infective Juvenile ◽  
Free Living ◽  
Initial Infection ◽  
Host Tissues ◽  
Insect Parasites

Entomopathogenic nematodes (EPNs) are potent insect parasites and have been used for pest control in agriculture. Despite the complexity of the EPN infection process, hosts are typically killed within 5 days of initial infection. When free-living infective juveniles (IJs) infect a host, they release their bacterial symbiont, secrete toxic products, and undergo notable morphological changes. Collectively, this process is referred to as “activation” and represents the point in a nematode’s life cycle when it becomes actively parasitic. The effect of different host tissues and IJ age on activation, and how activation itself is related to virulence, are not well understood. Here, we employed a recently developed bioassay, which quantifies IJ activation, as a tool to address these matters. Appreciating that activation is a key part of the EPN infection process, we hypothesized that activation would positively correlate to virulence. Using the EPNs Steinernema carpocapsae and S. feltiae we found that EPN activation is host-specific and influenced by infective juvenile age. Additionally, our data suggest that activation has a context-dependent influence on virulence and could be predictive of virulence in some cases such as when IJ activation is especially low.

scholarly journals First report of an entomopathogenic nematode from continental Portugal

2007 ◽  
Vol 44 (4) ◽  
pp. 226-229 ◽  
Author(s):  
V. Valadas ◽  
S. Boyle ◽  
P. Vieira ◽  
T. Kakouli-Duarte ◽  
M. Mota
Keyword(s):  
Entomopathogenic Nematodes ◽  
Entomopathogenic Nematode ◽  
Steinernema Feltiae ◽  
First Report ◽  
Nematode Genus

AbstractIn continental Portugal no information is available concerning the occurrence of entomopathogenic nematodes. During a survey in several different habitats from the southern regions of the country, several isolates where identified as Steinernema feltiae. This represents the first report of an entomopathogenic nematode genus for continental Portugal.

Characterisation of biological and biocontrol traits of entomopathogenic nematodes promising for control of striped flea beetle (Phyllotreta striolata)

Nematology ◽  
2018 ◽  
Vol 20 (6) ◽  
pp. 503-518 ◽  
Author(s):  
Xun Yan ◽  
Yinying Lin ◽  
Zhenmao Huang ◽  
Richou Han
Keyword(s):  
Culture System ◽  
Entomopathogenic Nematodes ◽  
Storage Temperature ◽  
Entomopathogenic Nematode ◽  
Flea Beetle ◽  
Cold Treatment ◽  
Heat Exposure ◽  
The Other ◽  
Commercial Strain ◽  
Phyllotreta Striolata

Summary The biological and biocontrol traits of two entomopathogenic nematode isolates, Steinernema pakistanense 94-1 (Sp94-1) and Heterorhabditis indica 212-2 (Hi212-2), were evaluated. The highest yield of infective juveniles (IJ) in monoxenic sponge culture system for Sp94-1 and Hi212-2 was 3.52 (± 0.45) × 105 and 7.08 (± 0.11) × 105 IJ g−1, respectively. The optimum storage temperature was 25°C for Sp94-1 and 14°C for Hi212-2. Sp94-1 showed greater tolerance to heat exposure and UV radiation, while S. carpocapsae All, a commercial strain, was more resistant to osmotic pressure, desiccation, cold treatment and hypoxia than the other tested isolates. Hi212-2 suppressed the Phyllotreta striolata larvae when applied at 1.5 × 109 IJ ha−1 or higher concentrations, while Sp94-1 suppressed the P. striolata larvae only when applied at 4.5 × 109 IJ ha−1. Our study indicates the possibility of commercialisation of the EPN isolates, and further confirms their efficacy against the P. striolata larvae in the field.

Mechanisms of specificity of association between the nematode Steinernema scapterisci and its symbiotic bacterium

Parasitology ◽  
1997 ◽  
Vol 114 (5) ◽  
pp. 483-488 ◽  
Author(s):  
P. S. GREWAL ◽  
M. MATSUURA ◽  
V. CONVERSE
Keyword(s):  
Galleria Mellonella ◽  
Entomopathogenic Nematode ◽  
Symbiotic Bacterium ◽  
Bacterial Symbiont ◽  
Steinernema Carpocapsae ◽  
Infective Juvenile ◽  
Symbiotic Bacteria ◽  
Bacterial Symbionts ◽  
First Report ◽  
Successful Isolation

We suggest a new mechanism for the maintenance of specificity of the association between the entomopathogenic nematode Steinernema scapterisci and its symbiotic bacteria. We evaluated the development and reproduction of infective and non-infective juvenile S. scapterisci in monoxenic combinations with its symbiotic bacteria, Xenorhabdus sp. ‘S’ and with the bacterial symbiont of Steinernema carpocapsae and Steinernema riobravis. Although development of non-infective stages occurred on all Xenorhabdus spp., the development of infective juveniles to the 4th stage (‘dauer’ recovery) was significantly delayed and reduced with X. nematophilus and Xenorhabdus sp. ‘R’, the bacterial symbionts of S. carpocapsae and S. riobravis, respectively. ‘Dauer’ recovery improved significantly when the cultures of X. nematophilus and Xenorhabdus sp. ‘R’ were supplemented with cell-free filtrates from Xenorhabdus sp. ‘S’. The infective juvenile S. scapterisci produced in all 3 cultures were virulent to Galleria mellonella larvae, confirming successful retention of Xenorhabdus from other steinernematids in their intestine. In fact, S. scapterisci infective juveniles containing X. nematophilus or Xenorhabdus sp. ‘R’ were more virulent to G. mellonella than those containing their natural symbiont, Xenorhabdus sp. ‘S’. We believe that this is the first demonstration of the symbiont-specific exit of infective juveniles from the ‘dauer’ phase which represents the finest level of specificity of bacteria–nematode association. This is also the first report of successful isolation of the natural symbiont of S. scapterisci.

scholarly journals Comparison of a Vintage and a Recently Released Nematicide for the Control of Root-Knot Nematodes and Side Effects on Two Entomopathogenic Nematodes

Plants ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1491
Author(s):  
Ioannis O. Giannakou ◽  
Stefanos Kamaras
Keyword(s):  
Chemical Control ◽  
Entomopathogenic Nematodes ◽  
No Reduction ◽  
The Other ◽  
Steinernema Feltiae ◽  
Vegetable Crops ◽  
Egg Hatching ◽  
Root Knot Nematodes ◽  
Tomato Plants ◽  
First Time

Root-knot nematodes can cause tremendous losses in vegetable crops. Farmers usually rely on synthetic nematicides to protect their crops. Recently, newly released nematicides are giving farmers an alternative in chemical control for nematodes. In the present study, the efficacy of vintage nematicide was compared to that of a relatively new nematicide, fluopyram. The latter was always more effective in substantially lower concentrations than oxamyl. Fluopyram paralyzed more than 80% J2s after 24 h immersion at the concentration of 0.25 μL L−1, while the percentage was increased close to 100% after immersion for 48 and 96 h. Similar levels of dead J2s were observed after immersion of J2s in oxamyl at concentrations higher than 8 μL L−1 (24 and 48 h) or 4 μL L−1 (96 h). An evident decrease of egg differentiation was observed when fluopyram concentration was increased to 8 μL L−1, while no significant decrease in egg differentiation was recorded at any concentration of oxamyl. Egg hatching was decreased at concentrations of fluopyram higher than 4 μL L−1, while no reduction was observed even when the concentration of oxamyl was increased to 64 μL L−1. The efficacy of fluopyram in soil was superior compared to that of oxamyl. For the first time, the systemic action of fluopyram is recorded in trials with tomato plants. On the other hand, compared to oxamyl, fluopyram seems to be more toxic to non-target organisms such as the entomopathogenic nematodes Steinernema feltiae and Heterorhabditis bacteriophora.

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