Survival of insect pathogenic and human clinical isolates ofPhotorhabdus luminescensin previously sterile soil

1999 ◽  
Vol 45 (3) ◽  
pp. 273-278 ◽  
Author(s):  
Bruce H Bleakley ◽  
Xiang Chen
Keyword(s):  
Entomopathogenic Nematodes ◽  
Soil Amendments ◽  
Plate Count ◽  
Limited Attention ◽  
Photorhabdus Luminescens ◽  
Bacterial Strains ◽  
Sterile Soil ◽  
Clinical Specimens ◽  
Casamino Acids ◽  
Over Time

Most characterized strains of the bacterium Photorhabdus luminescens are symbionts of entomopathogenic nematodes, whereas other strains have been isolated from human clinical specimens. The ability of P. luminescens strains to survive and grow in soil has received limited attention, with some studies indicating these bacteria have little or no ability to persist in soil. Survival and (or) growth of P. luminescens strains in previously sterilized soil, and examination of different soil amendments on their numbers in soil, have not been previously reported. Entomopathogenic P. luminescens (ATCC 29999) and a human clinical isolate (ATCC 43949) were introduced into a soil that had been sterilized by autoclaving, with or without different soil amendments, and bacterial numbers were estimated over time by viable plate count. In the previously sterilized soil receiving no exogenous amendments, numbers fell drastically over a week's time, followed by an increase in numbers by day 30. Treatments involving the addition of calcium carbonate and gelatin or casamino acids to soil usually resulted in higher bacterial numbers. For some sampling dates and soil treatments, there were statistically significant differences between the numbers of the two bacterial strains recovered from soil. The two strains of P. luminescens used in this study were able to survive and grow after being inoculated into previously sterilized soil.Key words: Photorhabdus luminescens, survival, soil.

Kallotenue papyrolyticum gen. nov., sp. nov., a cellulolytic and filamentous thermophile that represents a novel lineage (Kallotenuales ord. nov., Kallotenuaceae fam. nov.) within the class Chloroflexia

2013 ◽  
Vol 63 (Pt_12) ◽  
pp. 4675-4682 ◽  
Author(s):  
Jessica K. Cole ◽  
Brandon A. Gieler ◽  
Devon L. Heisler ◽  
Maryknoll M. Palisoc ◽  
Amanda J. Williams ◽  
...  
Keyword(s):  
Carbon Sources ◽  
Rrna Gene ◽  
Bacterial Strains ◽  
16S Rrna Gene Sequences ◽  
Content Type ◽  
Link Type ◽  
Casamino Acids ◽  
Ph Range ◽  
Dense Liquid ◽  
Cellulose Filter

Several closely related, thermophilic and cellulolytic bacterial strains, designated JKG1T, JKG2, JKG3, JKG4 and JKG5, were isolated from a cellulolytic enrichment (corn stover) incubated in the water column of Great Boiling Spring, NV. Strain JKG1T had cells of diameter 0.7–0.9 µm and length ~2.0 µm that formed non-branched, multicellular filaments reaching >300 µm. Spores were not formed and dense liquid cultures were red. The temperature range for growth was 45–65 °C, with an optimum of 55 °C. The pH range for growth was pH 5.6–9.0, with an optimum of pH 7.5. JKG1T grew as an aerobic heterotroph, utilizing glucose, sucrose, xylose, arabinose, cellobiose, CM-cellulose, filter paper, microcrystalline cellulose, xylan, starch, Casamino acids, tryptone, peptone, yeast extract, acetate, citrate, lactate, pyruvate and glycerol as sole carbon sources, and was not observed to photosynthesize. The cells stained Gram-negative. Phylogenetic analysis using 16S rRNA gene sequences placed the new isolates in the class Chloroflexia , but distant from other cultivated members, with the highest sequence identity of 82.5 % to Roseiflexus castenholzii . The major quinone was menaquinone-9; no ubiquinones were detected. The major cellular fatty acids (>5 %) were C18 : 0, anteiso-C17 : 0, iso-C18 : 0, iso-C17 : 0, C16 : 0, iso-C16 : 0 and C17 : 0. The peptidoglycan amino acids were alanine, ornithine, glutamic acid, serine and asparagine. Whole-cell sugars included mannose, rhamnose, glucose, galactose, ribose, arabinose and xylose. Morphological, phylogenetic and chemotaxonomic results suggest that JKG1T is representative of a new lineage within the class Chloroflexia , which we propose to designate Kallotenue papyrolyticum gen. nov., sp. nov., Kallotenuaceae fam. nov., Kallotenuales ord. nov. The type strain of Kallotenue papyrolyticum gen. nov., sp. nov. is JKG1T ( = DSM 26889T = JCM 19132T).

scholarly journals Bacterial Community Members Increase Bacillus subtilis Maintenance on the Roots of Arabidopsis thaliana

2020 ◽  
Vol 4 (4) ◽  
pp. 303-313
Author(s):  
Noam Eckshtain-Levi ◽  
Susanna Leigh Harris ◽  
Reizo Quilat Roscios ◽  
Elizabeth Anne Shank
Keyword(s):  
Arabidopsis Thaliana ◽  
Bacillus Subtilis ◽  
Crop Production ◽  
Crop Yields ◽  
Plant Root ◽  
Plant Roots ◽  
Plant Growth Promoting Bacteria ◽  
Bacterial Strains ◽  
Root Microbiome ◽  
Over Time

Plant-growth-promoting bacteria (PGPB) are used to improve plant health and promote crop production. However, because some PGPB (including Bacillus subtilis) do not maintain substantial colonization on plant roots over time, it is unclear how effective PGPB are throughout the plant growing cycle. A better understanding of the dynamics of plant root community assembly is needed to develop and harness the potential of PGPB. Although B. subtilis is often a member of the root microbiome, it does not efficiently monoassociate with plant roots. We hypothesized that B. subtilis may require other primary colonizers to efficiently associate with plant roots. We utilized a previously designed hydroponic system to add bacteria to Arabidopsis thaliana roots and monitor their attachment over time. We inoculated seedlings with B. subtilis and individual bacterial isolates from the native A. thaliana root microbiome either alone or together. We then measured how the coinoculum affected the ability of B. subtilis to colonize and maintain on A. thaliana roots. We screened 96 fully genome-sequenced strains and identified five bacterial strains that were able to significantly improve the maintenance of B. subtilis. Three of these rhizobacteria also increased the maintenance of two strains of B. amyloliquefaciens commonly used in commercially available bioadditives. These results not only illustrate the utility of this model system to address questions about plant–microbe interactions and how other bacteria affect the ability of PGPB to maintain their relationships with plant roots but also may help inform future agricultural interventions to increase crop yields. [Formula: see text] Copyright © 2020 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .

scholarly journals Mobile Dental Delivery System: An Effective Protocol for Hygiene and Disinfection

2020 ◽  
Vol 17 (5) ◽  
pp. 1603 ◽  
Author(s):  
Damien Offner ◽  
Gabriel Fernandez De Grado ◽  
Marion Strub ◽  
Laure Belotti ◽  
Stéphanie Deboscker ◽  
...  
Keyword(s):  
Dental Care ◽  
Care Delivery ◽  
Microbiological Quality ◽  
Plate Count ◽  
Heterotrophic Plate Count ◽  
Dental Procedures ◽  
Dental Care Delivery ◽  
Dental Unit Waterlines ◽  
Over Time

Mobile dental delivery systems (MDDSs) are receiving growing interest for reaching isolated patients, as well as in dental care for fragile and hospitalized patients, with the advantage of being able to be used from room to room or during general anesthesia (GA) in an operating room. Therefore, ensuring the care safety is crucial. The aim of this study was to elaborate and assess an MDDS maintenance protocol, containing the management of dental unit waterlines and adapted to specific conditions such as dental care under GA. A step-by-step protocol was established and implemented for an MDDS used during dental care under GA in children. Samples of the output water were collected at J0, J+1, 3, 6, 12, and 24 months, and cultured to observe the microbiological quality of the water. All the results (heterotrophic plate count at 22 °C, at 37 °C, and specific pathogenic germs sought) showed an absence of contamination. The protocol presented was effective over time and allowed ensuring the safety of care to be ensured when using MDDS, even during dental procedures under GA. As a result, it could be implemented by any dental care delivery structure wanting to reinforce the safety of its practice.

In vivo production of entomopathogenic nematodes suppressed by asymptomatic bacterial contaminants

Nematology ◽  
2020 ◽  
Vol 22 (8) ◽  
pp. 917-925
Author(s):  
Akanksha Upadhyay ◽  
Sharad Mohan
Keyword(s):  
Biological Control ◽  
Entomopathogenic Nematodes ◽  
Photorhabdus Luminescens ◽  
Ochrobactrum Anthropi ◽  
Progeny Production ◽  
Bacterial Contaminants ◽  
Significant Difference ◽  
Biological Control Of Insects

Summary Entomopathogenic nematodes (EPN) are excellent biological control agents possessing recycling ability as one of their major attributes. We report the presence of asymptomatic bacteria that can lead to disrupted or low progeny production in Heterorhabditis indica. In a one-to-one in vitro competitive bioassay with contaminants associated with H. indica cuticle, there was a significant suppression in the growth of Sphingomonas koreensis when stressed with the nematode symbiont Photorhabdus luminescens; however, P. luminescens was suppressed when sandwiched between Ochrobactrum anthropi. Bacillus bombysepticus associated with laboratory-reared Galleria when stressed by P. luminescens was significantly suppressed, but not so in the reverse assay. Both O. anthropi and B. bombysepticus were found to be insecticidal to Galleria larvae when fed orally. Tripartite interactive studies on the growth and multiplication of H. indica-P. luminescens symbionts in Galleria larvae, predisposed to S. koreensis, revealed no significant difference initially in the hermaphrodite formation, but subsequently there was a significant decline in the formation of amphimictic females and the final production of infective juveniles. In in vitro studies, none of the contaminants supported the growth and development of axenic H. indica. Adequate precautions should be taken to maintain proper hygiene to eliminate such contaminants while culturing the Galleria and EPN for use in the biological control of insects.

scholarly journals Deinococcus peraridilitoris sp. nov., isolated from a coastal desert

2007 ◽  
Vol 57 (7) ◽  
pp. 1408-1412 ◽  
Author(s):  
Fred A. Rainey ◽  
Margarida Ferreira ◽  
M. Fernanda Nobre ◽  
Keren Ray ◽  
Danielle Bagaley ◽  
...  
Keyword(s):  
Novel Species ◽  
Plate Count ◽  
Rrna Gene ◽  
Bacterial Strains ◽  
Phenotypic Data ◽  
Coastal Desert ◽  
Plate Count Agar ◽  
Radiation Resistant ◽  
The 16S Rrna Gene ◽  
Sequence Similarities

Three ionizing-radiation-resistant bacterial strains (designated KR-196, KR-198 and KR-200T) were isolated from a sample of arid soil collected from a coastal desert in Chile. The soil sample was irradiated before serial dilution plating was performed using one-tenth-strength plate count agar. Phylogenetic analysis of the 16S rRNA gene sequences showed these organisms to represent a novel species of the genus Deinococcus, having sequence similarities of 87.3–90.8 % with respect to recognized Deinococcus species. Strains KR-196, KR-198 and KR-200T were aerobic and showed optimum growth at 30 °C and pH 6.5–8.0. The major respiratory menaquinone was MK-8. The predominant fatty acids in these strains were 16 : 1ω7c, 16 : 0, 15 : 1ω6c, 17 : 0 and 18 : 0. The DNA G+C content of strain KR-200T was 63.9 mol%. Strains KR-196, KR-198 and KR-200T were found to be resistant to >10 kGy gamma radiation. On the basis of the phylogenetic, chemotaxonomic and phenotypic data, strain KR-200T represents a novel species of the genus Deinococcus, for which the name Deinococcus peraridilitoris sp. nov. is proposed. The type strain is KR-200T (=LMG 22246T=CIP 109416T).

scholarly journals Genome sequences of Photorhabdus luminescens strains isolated from entomopathogenic nematodes from southern India

Genomics Data ◽  
2015 ◽  
Vol 6 ◽  
pp. 46-47 ◽  
Author(s):  
Nagesh Mandadi ◽  
Christopher Hendrickson ◽  
Savithri Handanahal ◽  
Thippeswamy Rajappa ◽  
Nikhita Pai ◽  
...  
Keyword(s):  
Entomopathogenic Nematodes ◽  
Southern India ◽  
Photorhabdus Luminescens ◽  
Genome Sequences

scholarly journals 009 Susceptibility of Mexican Fruit Fly Larvae to Entomopathogenic Nematodes (Steinernematidae and Heterorhabditidae)

HortScience ◽  
2000 ◽  
Vol 35 (3) ◽  
pp. 389C-389
Author(s):  
Roberto Lezama-Gutierrez ◽  
Jaime Molina-Ochoa ◽  
Oscar L. Contreras-Ochoa ◽  
Martin Gonzalez-Ramirez ◽  
Oscar Rebolledo-Dominguez ◽  
...  
Keyword(s):  
Entomopathogenic Nematodes ◽  
Soil Surface ◽  
Fruit Fly ◽  
Infective Juvenile ◽  
Anastrepha Ludens ◽  
Distilled Water ◽  
Biological Control Agents ◽  
Mexican Fruit Fly ◽  
Sterile Soil ◽  
Third Instar Larvae

The susceptibility of third-instar larvae of Anastrepha ludens (Loew) to the entomopathogenic nematodes Steinernema carpocapsae (Weiser) (All and Tecomán strains), S. feltiae (Filiipjev), S. glaseri (Steiner) (NC strain), S. riobrave (Cabanillas, Poinar & Raulston), and Heterorhabditis bacteriophora Poinar (NC, Patronato, and Tecomán strains), was evaluated under laboratory conditions. Sterile distilled water (1.0 mL) with 4000 infective juvenile nematodes were applied on 300 g of moistened sterile soil into 1000-mL pots, and 20 third-instar larvae were placed on the soil surface, 1 mL of distilled water without nematodes was applied as control. Each nematode treatment was replicated four times. After nematode application, pots were incubated at 25 °C. Mortality of larvae and pupae was evaluated 6 and 12 d after inoculation. Cadavers of larvae and pupae were dissected and examined for the presence of nematodes. Our results showed that Mexican fruit larvae were susceptible to entomopathogenic nematodes. S. riobrave and S. carpocapsae All strain caused 90% of larval and pupae cumulative mortality, H. bactetiophora NC strain and S. feltiae killed more than 80%, whereas H. bacteriophora Tecomán and S. glaseri caused a 52.5% mortality. These results suggest that the nematodes S. riobrave and S. carpocapsae All strain have a potential as biological control agents against A. ludens.

scholarly journals Antibacterial effect of TiO2 modified with poly-amidoamine dendrimer – G3 on S. aureus and E. coli in aqueous solutions

2022 ◽  
Author(s):  
Soudabeh Alizadeh Matboo ◽  
Shahram Nazari ◽  
Ali Niapour ◽  
Mehdi Vosoughi Niri ◽  
Esrafil Asgari ◽  
...  
Keyword(s):  
Inhibitory Concentration ◽  
Antibacterial Properties ◽  
Plate Count ◽  
Bacterial Strains ◽  
Solution Ph ◽  
E Coli ◽  
Bacterial Removal ◽  
Mic Minimum Inhibitory Concentration ◽  
Paper Disc ◽  
Surface Plate

Abstract This study investigated the bacterial removal using TiO2 nanoparticles (NPs) modified with poly-amidoamine dendrimer macromolecule (PAMAM, G3). The PAMAM G3/TiO2 (nanohybrid) was used to specify antibacterial properties via broth microdilution (MBC-Minimum Bactericidal Concentration and MIC-Minimum Inhibitory Concentration- determination), paper disc diffusion, and surface plate count methods. The nanohybrid was characterized via the different techniques. The effects of different factors including initial bacteria count, run time, solution pH, and the nanohybrid concentration were studied. The nanohybrid cytotoxicity was studied on AGS and MKN45 cells line by MTT assay. It was revealed that the nanohybrid was effective in intercepting both bacterial strains growth. The MIC value for S. aureus and E. coli were determined to be 4 and 2 μg/mL, respectively. The MBC value for both strains were calculated to be 32 μg/mL. The results showed removal efficiency of 100% for S. aureus and E. coli bacteria in optimum situation. The decrease in cell viability in the dosage of 32 μg/mL after 72 h treatment for AGS and MKN45 cells line were shown to be 6.2 and 4.6%, respectively. The nanohybrid was able to decrease the S. aureus and E. coli count in solution, which meets the drinking water criterions aligned with WHO guidelines.

Job insecurity fluctuations and support towards Italian precarious schoolteachers

2020 ◽  
Vol 25 (6) ◽  
pp. 631-647
Author(s):  
Marianna Giunchi ◽  
Pedro Marques-Quinteiro ◽  
Chiara Ghislieri ◽  
Anne-Marie Vonthron
Keyword(s):  
Social Support ◽  
Job Insecurity ◽  
Small Sample Size ◽  
Well Being ◽  
School Principal ◽  
Small Sample ◽  
Limited Attention ◽  
Negative Consequences ◽  
Content Type ◽  
Over Time

PurposeThe negative consequences of job insecurity on the well-being of individuals are well known. However, the perceptions of job insecurity over time and how some factors such as social support may affect them have received limited attention. This study follows precarious schoolteachers for three weeks before the end of their contract to explore how their perceptions of job insecurity evolve over time.Design/methodology/approachThe participants were 47 precarious schoolteachers who first completed a general questionnaire, then a diary survey on nine occasions over the course of the three weeks. Data was analysed with MPLUS 7.3.FindingsThe results suggest intra-individual differences regarding the way job insecurity was perceived over time. An additional discovery was that support provided by the school principal was negatively related to changes in job insecurity over time.Research limitations/implicationsThe relatively small sample size, which includes only precarious schoolteachers, and the methodology complexity of the diary are limitations of this study.Practical implicationsThis study highlights the subjective nature of the perceptions of job insecurity. It also shows the importance of the school principal's social support towards precarious schoolteachers; therefore, practitioners should propose interventions to enhance the quality of principal–teachers relationships.Originality/valueThis study contributes to the literature by investigating how perceptions of job insecurity evolve over time and the role of social support.

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