scholarly journals Biological Control of Aedes albopictus: Obtained from the New Bacterial Candidates with Insecticidal Activity

Insects ◽  
2020 ◽  
Vol 11 (7) ◽  
pp. 403
Author(s):  
Handi Dahmana ◽  
Masse Sambou ◽  
Didier Raoult ◽  
Florence Fenollar ◽  
Oleg Mediannikov
Keyword(s):  
Biological Control ◽  
Aedes Albopictus ◽  
Insecticidal Activity ◽  
Bacterial Species ◽  
Larval Mortality ◽  
Bacillus Sphaericus ◽  
Supernatant Fraction ◽  
Bacterial Strains ◽  
Streptomyces Species ◽  
Vector Borne

Vector-borne deadly pathogens cause more than 700,000 deaths annually. They are transmitted by several vectors, among which the mosquito is the most important. Chemical compounds often have devastating side effects, leading to the abandonment of the majority of them. Biological control has been performed by using formulations of Bacillus sphaericus and Bacillus thuringiensis, but their intensive use has led to the emergence of resistance. Currently, the development of new alternative molecules is urgently needed, in order to use them in mosaics or in rotation with already known insecticides for the control of vectors, especially mosquitoes. Here, we attempted to identify bacterial species with potential anti-mosquito actions. Among bacterial strains isolated from dry sandy soil from Senegal, eleven strains from the Bacillales and Actinomycetales orders were chosen for the entomopathogenic activity experiments. Then, we tested their secondary metabolites, which were obtained from the supernatant fraction, and their cell wall and cytoplasmic compounds, which were found in the pellet fraction, in Aedes albopictus larvae, and compared the larval mortality rate with that obtained by using a commercial product. A total of 4/11 (36.36%) of the isolated species exhibited insecticidal activity. B. nealsonii, which is not a well-known bacterium, had the highest larvicidal effect with 70% of the larval mortality, which is highlighted for the first time. The Streptomyces species we isolated seem to be potential new species, and 3/5 (60%) of them exhibited insecticidal activity. Our study reports provide potential candidates for the identification of active molecules to be developed for strengthening the biological control of infectious diseases agents transmitted by mosquitoes.

scholarly journals Insecticidal activity of the metabolites of sand soil bacteria in Northern Senegal

2020 ◽  
Author(s):  
Handi Dahmana ◽  
Masse Sambou ◽  
Didier Raoult ◽  
Florence Fenollar ◽  
Oleg Mediannikov
Keyword(s):  
Insecticidal Activity ◽  
Molecular Mechanisms ◽  
Bacterial Species ◽  
Larval Mortality ◽  
Bacillus Sphaericus ◽  
Supernatant Fraction ◽  
Bacterial Strains ◽  
Vector Borne ◽  
Emergence Of Resistance ◽  
First Time

Abstract BackgroundVector-borne deadly diseases cause more than 700,000 deaths annually. They are transmitted by several vectors, among which the mosquito is the most important. Chemical compounds often have devastating side effects, which has led to the abandonment of the majority of them. Biological control has been performed by using formulations of Bacillus sphaericus and Bacillus thuringiensis, but their intensive use has led to the emergence of resistance. Currently, there is an urgent need to develop new alterative molecules from bacteria to use in mosaics or in rotation with already known insecticides and bacteria for the control of vectors, especially mosquitos. Here, we attempted to identify bacterial species with potential anti-mosquito actions.ResultsAmong 208 strains isolated from dry sandy soil from Senegal, eleven bacterial strains from the Bacillus genus (5) and Actinomycetales order (6) were chosen for the following experiments. Then, we tested their secondary metabolites, which were obtained from the supernatant fraction, and their cell wall and cytoplasmic compounds, which were found in the pellet fraction, in 3rd and early 4th Aedes albopictus larvae instars and compared the larval mortality rate with that obtained by using a commercial product. A total of 4/11 (36.4%) of the isolated species exhibited insecticidal activity. B. nealsonii, which is not a well-known bacterium, had the highest larvicidal effect with 70% larval mortality, which highlighted for the first time. The Streptomyces spp. we isolated seem to be potential new species, and 3/5 (60%) of them exhibited insecticidal activity.ConclusionThe bacterial strains isolated in this study may be used to identify the molecular mechanisms of their insecticidal activity.

scholarly journals Insecticidal Activity of Bacteria from Larvae Breeding Site with Natural Larvae Mortality: Screening of Separated Supernatant and Pellet Fractions

Pathogens ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 486 ◽  
Author(s):  
Handi Dahmana ◽  
Didier Raoult ◽  
Florence Fenollar ◽  
Oleg Mediannikov
Keyword(s):  
Biological Control ◽  
Insecticidal Activity ◽  
Breeding Site ◽  
Bacterial Strains ◽  
Activity Prediction ◽  
Pcr Screening ◽  
Breeding Sites ◽  
Insecticide Activity ◽  
New Compounds

Mosquitoes can transmit to humans devastating and deadly pathogens. As many chemical insecticides are banned due to environmental side effects or are of reduced efficacy due to resistance, biological control, including the use of bacterial strains with insecticidal activity, is of increasing interest and importance. The urgent actual need relies on the discovery of new compounds, preferably of a biological nature. Here, we explored the phenomenon of natural larvae mortality in larval breeding sites to identify potential novel compounds that may be used in biological control. From there, we isolated 14 bacterial strains of the phylum Firmicutes, most of the order Bacillales. Cultures were carried out under controlled conditions and were separated on supernatant and pellet fractions. The two fractions and a 1:1 mixture of the two fractions were tested on L3 and early L4 Aedes albopictus. Two concentrations were tested (2 and 6 mg/L). Larvae mortality was recorded at 24, 48 and 72 h and compared to that induced by the commercialized B. thuringiensis subsp. israelensis. Of the 14 strains isolated, 11 were active against the A. albopictus larvae: 10 of the supernatant fractions and one pellet fraction, and mortality increased with the concentration. For the insecticide activity prediction in three strains of the Bacillus cereus complex, PCR screening of the crystal (Cry) and cytolytic (Cyt) protein families characteristic to B. thuringiensis subsp. israelensis was performed. Most of the genes coding for these proteins’ synthesis were not detected. We identified bacterial strains that exhibit higher insecticidal activity compared with a commercial product. Further studies are needed for the characterization of active compounds.

scholarly journals Larvicidal potentiality, longevity and fecundity inhibitory activities of Bacillus sphaericus (Bs G3-IV) on vector mosquitoes, Aedes aegypti and Culex quinquefasciatus

2012 ◽  
Vol 44 (3) ◽  
pp. 15 ◽  
Author(s):  
Arjunan Nareshkumar ◽  
Kadarkarai Murugan ◽  
Indra Baruah ◽  
Pari Madhiyazhagan ◽  
Thiyagarajan Nataraj
Keyword(s):  
Aedes Aegypti ◽  
Culex Quinquefasciatus ◽  
Mosquito Control ◽  
Larval Mortality ◽  
Bacillus Sphaericus ◽  
Control Agent ◽  
Vector Borne Diseases ◽  
Vector Population ◽  
Intervention Measures ◽  
Vector Borne

Intervention measures to control the transmission of vector-borne diseases include control of the vector population. In mosquito control, synthetic insecticides used against both the larvae (larvicides) and adults (adulticides) create numerous problems, such as environmental pollution, insecticide resistance and toxic hazards to humans. In the present study, a bacterial pesticide,<em> Bacillus sphaericus</em> (Bs G3-IV), was used to control the dengue and filarial vectors, <em>Aedes aegypti</em> and <em>Culex quinquefasciatus</em>. <em>Bacillus sphaericus </em>(Bs G3-IV) was very effective against<em> Aedes aegypti</em> and <em>Culex quinquefasciatus</em>, showing significant larval mortality. Evaluated lethal concentrations (LC<sub>50</sub> and LC<sub>90</sub>) were age-dependent, with early instars requiring a lower concentration compared with later stages of mosquitoes. <em>Culex quinquefasciatus</em> was more susceptible to <em>Bacillus sphaericus</em> (Bs G3-IV) than was <em>Aedes aegypti</em>. Fecundity rate was highly reduced after treatment with different concentrations of <em>Bacillus sphaericus</em> (Bs G3-IV). Larval and pupal longevity both decreased after treatment with <em>Bacillus sphaericus</em> (Bs G3-IV), total number of days was lower in the <em>B. sphaericus</em> treatments compared with the control. Our results show the bacterial pesticide <em>Bacillus sphaericus </em>(Bs G3-IV) to be an effective mosquito control agent that can be used for more integrated pest management programs.

Insecticidal effects of some biological agents on Agelastica alni (Coleoptera: Chrysomelidae)

Biologia ◽  
2006 ◽  
Vol 61 (6) ◽  
Author(s):  
Kazım Sezen ◽  
Zihni Demirbağ
Keyword(s):  
Biological Control ◽  
Bacillus Thuringiensis ◽  
Insecticidal Activity ◽  
Biological Control Agent ◽  
Bacillus Sphaericus ◽  
Leaf Beetle ◽  
Control Agent ◽  
Biological Agents ◽  
Economic Damage ◽  
Melolontha Melolontha

AbstractThe alder leaf beetle (Agelastica alni L., Coleoptera: Chrysomelidae) causes approximately 10% of total economic damage to hazelnut product per year in Turkey. A. alni larvae are susceptible to several pathogens indigenous to the area in which these insects occur in Turkey. In the present study, in order to find a more effective and safer biological control agent against this common pest, we evaluated the various biological agents’ insecticidal activity during the four hazelnut seasons from 2002 to 2005 on the larvae of the alder leaf beetle collected from the vicinity of Trabzon, Turkey. The tested agents are 25 insect-originating bacteria, 2 bacterial toxins and 1 viral preparation. The results showed that the highest insecticidal activity was obtained by bacterial isolates at 1.8 × 109 bacteria/mL dose, within ten days on the larvae of A. alni. These are 90% for Bacillus thuringiensis biovar tenebrionis (4AA1), Bacillus sphaericus (Ar4, isolated from Anoplus roboris L., Col.: Curculionidae), and Bacillus thuringiensis (Mm2, isolated from Melolontha melolontha L., Col.: Scarabaeidae). Our results indicate that these isolates may be valuable as biological control agent.

scholarly journals The Conservation of Low Complexity Regions in Bacterial Proteins Depends on the Pathogenicity of the Strain and Subcellular Location of the Protein

Genes ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 451
Author(s):  
Pablo Mier ◽  
Miguel A. Andrade-Navarro
Keyword(s):  
Membrane Proteins ◽  
Outer Membrane ◽  
Bacterial Species ◽  
Outer Membrane Proteins ◽  
Subcellular Location ◽  
Low Complexity ◽  
Extracellular Proteins ◽  
Bacterial Strains ◽  
Bacterial Proteins ◽  
Protein Subcellular Location

Low complexity regions (LCRs) in proteins are characterized by amino acid frequencies that differ from the average. These regions evolve faster and tend to be less conserved between homologs than globular domains. They are not common in bacteria, as compared to their prevalence in eukaryotes. Studying their conservation could help provide hypotheses about their function. To obtain the appropriate evolutionary focus for this rapidly evolving feature, here we study the conservation of LCRs in bacterial strains and compare their high variability to the closeness of the strains. For this, we selected 20 taxonomically diverse bacterial species and obtained the completely sequenced proteomes of two strains per species. We calculated all orthologous pairs for each of the 20 strain pairs. Per orthologous pair, we computed the conservation of two types of LCRs: compositionally biased regions (CBRs) and homorepeats (polyX). Our results show that, in bacteria, Q-rich CBRs are the most conserved, while A-rich CBRs and polyA are the most variable. LCRs have generally higher conservation when comparing pathogenic strains. However, this result depends on protein subcellular location: LCRs accumulate in extracellular and outer membrane proteins, with conservation increased in the extracellular proteins of pathogens, and decreased for polyX in the outer membrane proteins of pathogens. We conclude that these dependencies support the functional importance of LCRs in host–pathogen interactions.

scholarly journals Isolation and efficacy of two bacterial strains antagonists of Erwinia amylovora and Pectobacterium carotovorum

2021 ◽  
Vol 31 (1) ◽  
Author(s):  
M’hamed BENADA ◽  
Boualem BOUMAAZA ◽  
Sofiane BOUDALIA ◽  
Omar KHALADI
Keyword(s):  
Fire Blight ◽  
Erwinia Amylovora ◽  
Bacterial Species ◽  
Crop Protection ◽  
Soft Rot ◽  
Causal Agent ◽  
Plant Diseases ◽  
Ecological Niches ◽  
Pectobacterium Carotovorum ◽  
Bacterial Strains

Abstract Background The development of ecofriendly tools against plant diseases is an important issue in crop protection. Screening and selection process of bacterial strains antagonists of 2 pathogenic bacterial species that limit very important crops, Erwinia amylovora, the causal agent of the fire blight disease, and Pectobacterium carotovorum, the causal agent of bacterial potato soft rot, were reported. Bacterial colonies were isolated from different ecological niches, where both pathogens were found: rhizosphere of potato tubers and fruits and leaves of pear trees from the northwest region of Algeria. Direct and indirect confrontation tests against strains of E. amylovora and P. carotovorum were performed. Results Results showed a significant antagonistic activity against both phytopathogenic species, using direct confrontation method and supernatants of cultures (p<0.005). In vitro assays showed growth inhibitions of both phytopathogenic species. Furthermore, results revealed that the strains of S. plymuthica had a better inhibitory effect than the strains of P. fluorescens against both pathogens. In vivo results on immature pear fruits showed a significant decrease in the progression of the fire blight symptoms, with a variation in the infection index from one antagonistic strain to another between 31.3 and 50%, and slice of potato showed total inhibition of the pathogen (P. carotovorum) by the antagonistic strains of Serratia plymuthica (p<0.005). Conclusion This study highlighted that the effective bacteria did not show any infection signs towards plant tissue, and considered as a potential strategy to limit the fire blight and soft rot diseases.

In vitro evaluation of the effect of nicotine, cotinine, and caffeine on oral microorganisms

2008 ◽  
Vol 54 (6) ◽  
pp. 501-508 ◽  
Author(s):  
Karina Cogo ◽  
Michelle Franz Montan ◽  
Cristiane de Cássia Bergamaschi ◽  
Eduardo D. Andrade ◽  
Pedro Luiz Rosalen ◽  
...  
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
High Performance ◽  
Culture Media ◽  
Bacterial Species ◽  
In Vitro Study ◽  
Bacterial Strains ◽  
Planktonic Cells ◽  
Susceptibility Tests

The aim of this in vitro study was to evaluate the effects of nicotine, cotinine, and caffeine on the viability of some oral bacterial species. It also evaluated the ability of these bacteria to metabolize those substances. Single-species biofilms of Streptococcus gordonii , Porphyromonas gingivalis , or Fusobacterium nucleatum and dual-species biofilms of S. gordonii – F. nucleatum and F. nucleatum – P. gingivalis were grown on hydroxyapatite discs. Seven species were studied as planktonic cells, including Streptococcus oralis , Streptococcus mitis , Propionibacterium acnes , Actinomyces naeslundii , and the species mentioned above. The viability of planktonic cells and biofilms was analyzed by susceptibility tests and time-kill assays, respectively, against different concentrations of nicotine, cotinine, and caffeine. High-performance liquid chromatography was performed to quantify nicotine, cotinine, and caffeine concentrations in the culture media after the assays. Susceptibility tests and viability assays showed that nicotine, cotinine, and caffeine cannot reduce or stimulate bacterial growth. High-performance liquid chromatography results showed that nicotine, cotinine, and caffeine concentrations were not altered after bacteria exposure. These findings indicate that nicotine, cotinine, and caffeine, in the concentrations used, cannot affect significantly the growth of these oral bacterial strains. Moreover, these species do not seem to metabolize these substances.

scholarly journals Virulence of entomopathogenic nematodes (Rhabditida: Steinernematidae and Heterorhabditidae) for the control of Diabrotica speciosa germar (coleoptera: chrysomelidae)

2011 ◽  
Vol 35 (6) ◽  
pp. 1149-1156 ◽  
Author(s):  
Viviane Santos ◽  
Alcides Moino Junior ◽  
Vanessa Andaló ◽  
Camila Costa Moreira ◽  
Ricardo Alves de Olinda
Keyword(s):  
Biological Control ◽  
Entomopathogenic Nematodes ◽  
Entomopathogenic Nematode ◽  
Larval Mortality ◽  
Steinernema Glaseri ◽  
Soil Insects ◽  
Diabrotica Speciosa ◽  
Pupal Mortality

Entomopathogenic nematodes (EPNs) are used in biological control of soil insects and show promise in the control of D. speciosa. The objective of this work was to evaluate the potential of native and exotic entomopathogenic nematode isolates in the control of D. speciosa under laboratory and greenhouse conditions. Results showed that all of EPNs caused larval mortality. The most virulent were Heterorhabditis sp. RSC01 (94%), Steinernema glaseri (84%), Heterorhabditis sp. JPM04 (82%) and Heterorhabditis amazonensis RSC05 (78%). There was no effect of the Heterorhabditis sp. RSC01 and S. glaseri isolates on eggs. The maximum mortality of D. speciosa larvae by Heterorhabditis sp. RSC01 was observed at a concentration of 300 IJ/ insect, while by S. glaseri observed the highest mortality at the concentration of 200 IJ/ insect. The Heterorhabditis sp. RSC01 isolate caused over 80% pupal mortality at a concentration of 250 IJ/insect. The virulence of Heterorhabditis sp. RSC01 and S. glaseri was affected by temperature. The Heterorhabditis sp. RSC01 isolate caused reduction in larva survival under greenhouse conditions at all of the tested concentrations and there was no difference in mortality among different concentrations of infectid juveniles.

scholarly journals Polymeric Nanoparticles Active against Dual-Species Bacterial Biofilms

Molecules ◽  
2021 ◽  
Vol 26 (16) ◽  
pp. 4958
Author(s):  
Jessa Marie V. Makabenta ◽  
Jungmi Park ◽  
Cheng-Hsuan Li ◽  
Aritra Nath Chattopadhyay ◽  
Ahmed Nabawy ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Laser Scanning ◽  
Polymeric Nanoparticles ◽  
Bacterial Species ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Bacterial Biofilms ◽  
Global Public Health ◽  
Bacterial Strains

Biofilm infections are a global public health threat, necessitating new treatment strategies. Biofilm formation also contributes to the development and spread of multidrug-resistant (MDR) bacterial strains. Biofilm-associated chronic infections typically involve colonization by more than one bacterial species. The co-existence of multiple species of bacteria in biofilms exacerbates therapeutic challenges and can render traditional antibiotics ineffective. Polymeric nanoparticles offer alternative antimicrobial approaches to antibiotics, owing to their tunable physico-chemical properties. Here, we report the efficacy of poly(oxanorborneneimide) (PONI)-based antimicrobial polymeric nanoparticles (PNPs) against multi-species bacterial biofilms. PNPs showed good dual-species biofilm penetration profiles as confirmed by confocal laser scanning microscopy. Broad-spectrum antimicrobial activity was observed, with reduction in both bacterial viability and overall biofilm mass. Further, PNPs displayed minimal fibroblast toxicity and high antimicrobial activity in an in vitro co-culture model comprising fibroblast cells and dual-species biofilms of Escherichia coli and Pseudomonas aeruginosa. This study highlights a potential clinical application of the presented polymeric platform.

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