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Ciprofloxacin pre-exposure influences individual cell MIC and heteroresistance of bacteria inside microfluidic droplets
No full textData files for article entitled "Ciprofloxacin pre-exposure influences individual cell MIC and heteroresistance of bacteria inside microfluidic droplets", and includes the code for analysis of droplet images, code for further analysis to do Gompertz fitting, distribution etc</p
The impact of pesticides on apple mite communities
Get PDFLaboratory, field and semi-field experiments have been carried out on the predatory mites Kampimodromus aberrans, Amblyseius andersoni, Typhlodromus pyri and Phytoseius finitimus in order to optimize biological control strategies against phytophagous mites in apple orchards. The first experiment concerned the augmentative releases of K. aberrans in organic and conventional apple orchards. The most frequent insecticides used in organic orchards were pyrethrins and spinosad, whereas neonicotinoids, OPs and IGRs were used in conventional orchards. K. aberrans releases were successful and predatory mites were significantly higher in released than in control plots. Moreover, populations were high in organic orchards compared to conventional orchards. Amblyseius andersoni was naturally occurring in all orchards. In 2010, no effect of K. aberrans release and orchard management were observed on A. andersoni populations but in 2011 A. andersoni population densities were low in released plots compared to control plots. In organic orchards located at Spresiano releases were made on two cultivars, i.e., Florina and Golden Delicious. In both 2010 and 2011 releases, K. aberrans population densities were higher in release than in control plots of both cultivars. K. aberrans population increased during the three years on Florina but not in Golden Delicious orchard. On the latter A. andersoni population densities were lower in released than in control plots. In conventional orchards K. aberrans did not establish probably because of a series of non-selective insecticide and fungicide treatments. However, the use of spinosad was associated to a decline of predatory mite populations in organic orchards.
The second experiment considered interspecific predation among K. aberrans, A. andersoni, T. pyri and P. finitimus. All four predators fed with heterospecific larvae were able to survive some weeks laying a number of eggs. A. andersoni consumed more T. pyri and P. finitimus than K. aberrans larvae and its fecundity was higher on the first two prey species. A diet based on T. pyri larvae was associated to the highest conversion rate of food into egg biomass; longevity was higher for predatory mite females fed with K. aberrans larvae. K. aberrans preyed more P. finitimus than T. pyri and A. andersoni larvae and its fecundity resulted higher on the first species. The conversion of food into egg biomass did not show precise trend while the longevity of K. aberrans resulted higher when fed with A. andersoni. Typhlodromus pyri consumed more P. finitimus and K. aberrans than A. andersoni larvae and laid more eggs on the first two species. Phytoseius finitimus preyed more K. aberrans and T. pyri than A. andersoni larvae but fecundity was not affected by prey; predatory mite females fed with A. andersoni larvae were more efficient in converting food into egg biomass but those fed with K. aberrans larvae lived longer. In terms of predation rate and fecundity, A. andersoni seems to be advantaged over T. pyri, T. pyri over K. aberrans, and A. andersoni, K. aberrans and T. pyri over P. finitimus. The performance of A. andersoni, K. aberrans and T. pyri in terms of predation rate and fecundity proved to be better of P. finitimus larvae than on other prey. The low prey consumption and fecundity of the latter suggest that is disadvantaged in interspecific predation. The comparison between pollen and prey diets confirmed the positive effect of pollen on the fecundity of all four predatory mite species.
The third experiment deals with the effects of insecticides, frequently applied in apple orchards, on K. aberrans in field and laboratory conditions. Insecticides including chlorpyrifos, thiacloprid, acetamiprid, lufenuron, indoxacarb, methoxyfenozide and etofenprox were tested. In field studies etofenprox was the most detrimental pesticide to predatory mites. It caused dramatic effects on K. aberrans populations and induced spider mite outbreaks. In other trials tau-fluvalinate and spinosad did similar effects. In laboratory studies we assessed lethal and sub-lethal effects for each pesticide tested. Spinosad, tau-fluvalinate, thiamethoxam, clothianidin and imidacloprid were included. Etofenprox, spinosad with tau-fluvalinate proved to be harmful insecticides to K. aberrans in terms of lethal effects. Neonicotinoids did not affect survival so much but their sub-lethal effects were more prominent in terms of fecundity. Other pesticides such as chlorpyrifos, indoxacarb, lufenuron and methoxyfenozide also significantly reduced fecundity in K. aberrans at a lower level.
In the fourth study we explored the role of pollen in alleviating the effects of pesticides on K. aberrans at individual and population levels. In the first part we tested biological and demographic parameters of K. aberrans on pollen and Panonychus ulmi. K. aberrans was reared individually on P. ulmi and on pollen. Both food sources allowed for predatory mites survival, development and reproduction. Pollen was preferred food as compared to P. ulmi. Total fecundity and survival rates of K. aberrans were higher on pollen than on tetranychids. Developmental times of protonymphs, deutonymphs and adults of K. aberrans were longer on P. ulmi than on pollen. Life-table parameters of K. aberrans were positively affected by pollen. The second part deals with the interactions of pesticides, pollen and K. aberrans in semi-field conditions. Experimental factors were: insecticide application and pollen application . Predatory mites were released on 3-4 shoots per plant 7 days before insecticide applications. Typha latifolia pollen was used. Insecticide application, particularly spinosad, determined a reduction in K. aberrans abundance. Pollen applications were associated to an increase in predatory mite population. Significant interaction between pollen applications was observed: pollen application mitigated the effect of chlorpyrifos (because of its compensation of sublethal effects on fecundity) but no effect was observed on spinosad treated plants.
In the last work mechanisms of resistance to chlorpyrifos due to mutations in insensitive Acetylcholinesterase (AChE) in K. aberrans was investigated. AChE cDNA was cloned. The cloning strategy relied on the AChE sequence of Tetranychus urticae. To obtain the homologous cDNA sequence in K. aberrans, degenerate primers were designed on conserved functional domains of the annotated AChEs in Metaseiulus occidentalis genome, and combined with 5’-3’ rapid amplification of cDNA ends. When the cloned AChE sequence was compared between K. aberrans sensible and resistant strains, only a Glycine to Serine (G119S) substitution was detected while both AChE sequences had a Phenylalanine residue at 331 position. These results excluded the F331W mutation as responsible for chlorpyrifos target site resistance in K. aberrans but it opened interrogatives about the role of G119S. Indeed the G119S substitution had been already described in mosquitoes Anopheles gambiae and Culex pipiens where it led to AChE1 insensitivity or reduced AChE1 activity. On the contrary, the same aminoacid change in T. urticae AChE sequence was associated with a more moderate decrease in chlorpyrifos response. So a species-specific effect of this substitution cannot be kept out. In any case, site oriented sequencing of AChE cDNA, confirmed the presence of G119S substitution in further three resistant strains of the mite predator as well as the absence of F331W mutation. At the same time, two additional sensible strains, displayed a Glycine at the position 119, instead of Serine, in their AChE sequence. Altogether, these findings might suggest that the G119S polymorphism was involved in the polygenic control of the resistant phenotype. In addition or alternatively, the mutated AChE might be in linkage with one of the genetic determinants which affect the insecticide sensitivity in K. aberrans
Does pollen availability mitigate the impact of pesticides on generalist predatory mites?
No full textThe effect of the provision of pollen on the impact of pesticides on the predatory mite Kampimodromus aberrans was assessed in the laboratory and in a potted plant experiment. Survival and fecundity of predatory mites were reduced by insecticides, and spinosad was more toxic than chlorpyrifos. High pollen application frequency reduced the sub-lethal effect induced by chlorpyrifos. On potted plants, pollen applications reduced the impact of chlorpyrifos on K. aberrans. Results obtained here highlight that the provision of fresh pollen is of particular importance for predatory mites when pesticides are applied
A single nucleotide polymorphism in the acetylcholinesterase gene of the predatory mite Kampimodromus aberrans (Acari: Phytoseiidae) is associated with chlorpyrifos resistance
Get PDFThe predatory mite Kampimodromus aberrans (Oudemans) (Acari: Phytoseiidae) is one of the most important biocontrol agents of herbivorous mites in European perennial crops. The use of pesticides, such as
organophosphate insecticides (OPs), is a major threat to the success of biocontrol strategies based onpredatory mites in these cropping systems. However, resistance to OPs in K. aberrans has recently been
reported. The present study investigated the target site resistance mechanisms that are potentially involved in OP insensitivity. In the herbivorous mite Tetranychus urticae Koch (Acari: Tetranychidae),
resistance to OPs is due to a modified and insensitive acetylcholinesterase (AChE; EC: 3.1.1.7) that bears amino acid substitution F331W (AChE Torpedo numbering). To determine whether the predators and
prey have evolved analogous molecular mechanisms to withstand the same selective pressure, the AChE cDNA from a putative orthologous gene was cloned and sequenced from susceptible and resistant
strains of K. aberrans. No synonymous mutation coding for a G119S substitution was determined to be strongly associated with the resistant phenotype instead of the alternative F331W. Because the same
mutation in T. urticae AChE was not associated with comparable levels of chlorpyrifos resistance, the role of the G119S substitution in defining insensitive AChE in K. aberrans remains unclear. G119S AChE genotyping
can be useful in ecological studies that trace the fate of resistant strains after field release or in marker-assisted selection of improved populations of K. aberrans to achieve multiple resistance phenotypes through gene pyramiding. The latent complexity of the target site resistance in K. aberrans vs. that of T. urticae is also discussed in the context of data from the genome project of the predatory mite Metaseiulus occidentalis (Nesbitt) (Acari: Phytoseiidae)
Augmentative releases of the predatory mite Kampimodromus aberrans in organic and conventional apple orchards
No full textExperimental releases of the predatory mite Kampimodromus aberrans (Oudemans) were conducted in
organic and conventional apple (Malus domestica Borkh.) orchards located in North-eastern Italy. The most frequent insecticides used in organic orchards were pyrethrins and spinosad,
whereas neonicotinoids, organophosphates and insect growth regulators were mostly used in conventional
orchards. K. aberrans population levels were significantly higher in release plots as compared to
control plots and K. aberrans populations were higher in organic compared to conventional orchards. In conventional orchards, K. aberrans released in 2010 and 2011 did not establish probably because of a series of non-selective insecticide and fungicide treatments.
In one experimental site, releases were evaluated in two organic orchards, one of Florina cv. and the
other of Golden Delicious cv., managed with the same cropping systems. On Florina, K. aberrans population
appeared to be larger than on Golden Delicious suggesting a potential role of leaf morphology in
predatory mite colonization. On Golden Delicious, A. andersoni population densities were lower in
release than in control plots. Implications for mite management in organic and conventional orchards are
discussed
Impact of pesticides on phytophagous and predatory mites: case-studies in annual and perennial crop systems
No full textPredation on heterospecific larvae by adult females of Kampimodromus aberrans, Amblyseius andersoni, Typhlodromus pyri and Phytoseius finitimus (Acari: Phytoseiidae)
No full textThe predatory mites Kampimodromus aberrans (Oudemans), Amblyseius andersoni (Chant), Typhlodromus pyri Scheuten and Phytoseius finitimus Ribaga are important biological control agents in orchards and vineyards in Europe and elsewhere. They can coexist in the same habitat and engage in intraguild predation (IGP). In the laboratory we evaluated biological parameters of these predatory mites fed with heterospecific larvae considered as intraguild prey (IG-prey). Results suggest that A. andersoni should be considered the superior intraguild predator, while Phytoseius finitimus appeared to suffer from intraguild predation. The profiles of K. aberrans and T. pyri were less definite
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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