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Evaluating the lethal and pre lethal effects of a range of fungi against adult Anopheles stephensi mosquitoes

Evaluating the lethal and pre lethal effects of a range of fungi against adult Anopheles stephensi mosquitoes

The nature and extent of the lethal and pre-lethal effects of a fungal biopesticide will depend on the fungal isolate, the dose applied, the efficiency of dose transfer (affected by formulation, substrate and exposure time) and the temperature during fungal incubation in the vec- tor [12,31-33]. To date around forty experimental studies have been reported examining some aspect of fungal infec- tion on adult mosquito vectors [12,13,15-19,21-24,31-57]. These studies include multiple fungal isolates from eight genera and twenty-one species. In spite of this diversity, the majority of recent studies consider only a handful of fungal isolates and have tended to focus on virulence alone. This study evaluated the virulence of 17 isolates of the entomopathogenic fungi Beauveria bassiana , Metarhizium anisopliae , M. acridum and Isaria farino- sus against the Asian vector mosquito Anopheles ste- phensi . In addition these isolates ability to affect feeding propensity and the relationship between virulence and alterations in feeding behaviour following fungal infec- tion was assessed. These results are discussed in the context of making rational choices for malaria control products.

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The sub-lethal effects of repeated cold exposure in insects

The sub-lethal effects of repeated cold exposure in insects

of the interactions between ecological processes and immune function (Rolff and Siva- Jothy, 2003). Although research on the effects of temperature extremes on invertebrate immune function is limited, mild cold stress has been shown to improve survival of fungal infection in D. melanogaster (LeBourg et al., 2009) whereas snails given repeated high temperature shocks have decreased immune function (Seppälä and Jokela, 2011). I found that, rather than trading off allocation to immune function for repairing freeze damage, P. isabella caterpillars have increased immune response to a fungal challenge after multiple freeze-thaw cycles. I did not investigate the mechanisms underlying this improvement in immune function, however I note that repeated freezing damages Malpighian tubules and hemocytes (Figure 4.6). This damage could potentially induce a wounding response leading to increased immune function through the phenoloxidase pathway (Cerenius and Söderhäll, 2004; Marmaras et al., 1996). Alternatively, this increased immune function could be a result of a generalized stress response—for example, Hsp70 is upregulated in many insect species after cold shock (Sinclair et al., 2007) or as part of seasonal hardening (Rinehart et al., 2007) and is also important in the immune responses in vertebrates (Pockley, 2003), suggesting a link between cold stress and immune responses in insects. Given that the spores of the species of fungus I used are found broadly and abundantly through Ontario (up to 70% of sites sampled, Bidochka et al., 1998), and that entomopathic fungi in general are common (91% of sites sampled, Bidochka et al., 1998), I suggest that overwintering immune function is an important, yet neglected, part of insect overwintering ecology.

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Sub Lethal Effects of Cypermethrin and Oxyfluorfen on Stress Enzyme Activities of Earthworm Species, Eisenia foetida Savigny, 1826

Sub Lethal Effects of Cypermethrin and Oxyfluorfen on Stress Enzyme Activities of Earthworm Species, Eisenia foetida Savigny, 1826

Earthworms are common soil organisms in moist environment and play an important role in improving structure and fertility of soil ecosystems [2]. It has been indicated that earthworms may represents up to 60-80% of the total animal biomass in soil [3]. Unlike many other soil organisms that are protected by thick cuticle on the exterior of their bodies, earthworms are protected by thin cuticle and therefore these are particularly susceptible to soil chemicals [4]. The bioaccumulation of insecticides in earthworms may not lead to significant effects to the animal itself, but may produce serious damages to higher tropic levels [5]. Therefore earthworms are suitable bio indicators of soil contamination and can be used to provide safety thresholds for insecticides applications and also used as key index of eco toxicology diagnosis [6,7].

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Pre-clinical assays predict pan-African Echis viper efficacy for a species-specific antivenom.

Pre-clinical assays predict pan-African Echis viper efficacy for a species-specific antivenom.

type lectins) [15]. However, each pathogenic toxin family was represented in all the Echis species [15] – a result suggesting the possibility that EchiTAbG would have cross-Echis species efficacy. However, we were also aware of previous clinical failures of the ‘heterologous’ administration of Echis species-specific antivenoms [33,34]. Consequently, and in line with WHO recommendations [17], we performed here a series of immunological assays examining the immunological venom cross reactivity of ovine IgG raised against each representative Echis species. The results of these assays, which were designed to measure IgG titre, specificity and relative avidity to venoms in reduced and native states, indicated a very considerable degree of immunological cross- reactivity of each species-specific IgG antisera to each Echis venom. However, EchiTAbG was ineffective in neutralising the in vivo lethal effects of E. c. sochureki. This indicates that while these immunological tests provide informative and comprehensive immunological profiles of an antivenom, they can not yet replace pre-clinical in vivo testing to indicate the efficacy of an antivenom. The most important result of the study was that EchiTAbG neutralises the lethal effects of venom from East and North-East African Echis species (E. p. leakeyi and E. coloratus) with an efficacy equal to that it shows against E. ocellatus from West Africa. A recent study reports a similar potential for the other EchiTAb Study Table 3. Venom lethality and venom-neutralising efficacy of (A) EchiTAbG and (B) the E.c. sochureki IgG antisera.

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The Toxicity of 10W-40 Motor Oil on Zebrafish Early Life Stages

The Toxicity of 10W-40 Motor Oil on Zebrafish Early Life Stages

The WAF of 10W-40 motor oil resulted in increased lethal effects and sublethal effects on zebrafish embryonal development. Lethality progressively increased from lower to higher concentrations of the WAF motor oil. The malformations of embryo-larvae and body length of larvae were the phenotypic endpoints to assess developmental toxicity of WAF motor oil. The overall results of the present study indicated that Figure 1. Acute lethal effects and sublethal effect in zebrafish embryos exposed to 10.0 v/v WAF motor oil. A) Normal embryo (24 hpf) with clearly somites, well-developed head, and tail. B) 24-hpf embryo exposed to car oil showing egg coagulation, C) showing non-formation of somites D) showing incomplete gastrulation. T; tail, CH; chorion, H; head, YS; yolk sac, V; vertebra, S; somite. Bar 500 µm.

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Predation Fear, Prey Behavior, and Community Structure: A Brief Review of Their Relationship

Predation Fear, Prey Behavior, and Community Structure: A Brief Review of Their Relationship

Behaviorally-mediated effects of predators on prey have become considered as the most important aspect when compared to the density-mediated effects in affecting lower trophic levels(Kuijper et al., 2013).There is an enhancing recognition that indirect, non-lethal predator effects are also important or even more important than their direct lethal effects. Predators may indirectly impact ungulates by altering their distribution towards less risky types of habitat. The relationships between prey personality and predator hunting mode have affected the survival and behaviour of prey. This has a large potential to control trophic cascades and acts as a mechanism to maintain intraspecific trait variation(Belgrad & Griffen, 2016). Fear of predation has slowed down the plant-litter decomposition (Davis, Carlson, Bradley, Warner, & Caselle, 2017; Hawlena, Strickland, Bradford, & Schmitz, 2012).

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Histopathological Alterations in the Gill, Liver and Brain of Cyprinus Carpio on Exposure to Quinalphos

Histopathological Alterations in the Gill, Liver and Brain of Cyprinus Carpio on Exposure to Quinalphos

Pesticides have been widely used all over the world to control insects, pests and disease vectors. They ultimately find their way into aquatic habitats such as rivers, lakes and ponds, and have been found to be highly toxic not only to fish but also to the organisms, which constitute the food chain [1-3]. Moreover, Agriculture, as the largest consumer of freshwater and as a major cause of reduction of surface and groundwater resources through erosion and chemical runoff directly correlates with the loss of water quality [4- 13]. Pesticides in general, are used very extensively in agriculture, forestry, public health and in veterinary practices. Hence, it is necessary to study the immediate and chronic effects of pesticides on fish, which form a part of human diet. These compounds have a tendency to accumulate in small quantities in lower fish food organisms

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Effects of sub-lethal concentrations of copper ammonium acetate, pyrethrins and atrazine on the response of Escherichia coli to antibiotics [version 1; peer review: 2 approved, 1 approved with reservations]

Effects of sub-lethal concentrations of copper ammonium acetate, pyrethrins and atrazine on the response of Escherichia coli to antibiotics [version 1; peer review: 2 approved, 1 approved with reservations]

R (version 3.2.0) was used for all statistical analyses (R Core Team, 2013). In experiments testing the responses to antibiot- ics during exposure to biocides we were interested in effects on EoP that were different in antibiotic+biocide combinations compared to either substance in isolation. We therefore tested the log-transformed EoP scores using a multifactor analysis of variance (ANOVA) by evaluating the significance of the anti- biotic by biocide interaction term. Antibiotic concentrations were treated as separate categories in the ANOVA. Plots of residuals were used to test for violations of assumptions. We fit these models using the lm function.

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The (non)effects of lethal population control on the diet of Australian dingoes

The (non)effects of lethal population control on the diet of Australian dingoes

Our results demonstrate that lethal dingo control did not alter dingo dietary diversity or similarly at our study sites. Brillouin’s index values showed that the diversity of prey consumed by dingoes was near-identical between baited and unbaited areas at each site, indicating that dingoes in baited areas selected neither a wider nor narrower range of prey than dingoes in unbaited areas. Pianka’s index values showed that the overall proportion of various prey consumed by dingoes was also either identical or near- identical between baited and unbaited areas; a trend reflected in results for individual surveys as well (Table 4; Fig. 4). This indicates that dingoes in baited and unbaited areas consumed the same proportion of various prey independent of the diversity or suite of prey species available (Table 5, Fig. 2). That temporal trends in the proportion of scats containing primary dingo prey were also similar between baited and unbaited areas further shows that prey consumption by dingoes is independent of dingo control (Fig. 3). These findings were consistent between sites dominated by the availability of large prey (Todmorden), small prey (Quinyam- bie) or mixed-sized prey (Cordillo Downs), suggesting that these results may be common across different ecosystems with different mammal assemblages.

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LETHAL AND SUBLETHAL EFFECTS OF TOXICANTS ON BUMBLE BEE POPULATIONS: A MODELLING APPROACH

LETHAL AND SUBLETHAL EFFECTS OF TOXICANTS ON BUMBLE BEE POPULATIONS: A MODELLING APPROACH

Understanding the mechanisms underlying the effects of resource availability on bumble bee population growth is an increasing focus of field and theoretical studies (Williams et al. 2012; Winfree et al. 2012); a recent study by Crone & Williams (2016) illustrates the importance of parsing out the relative importance of putatively important drivers (e.g., colony growth rates and floral resource availability) of bumble bee population outcomes. Less is known about combinations of reduced resource provisioning and diminished survivorship that may result from exposure to pesticides or mixtures of pesticides that have both acute and sublethal effects, though the potential for multiplicative effects have been demonstrated in recent elegant experiments (e.g., Gill et al. 2012). Our simulations suggest that, even at low levels, sublethal effects such as reduced pollen foraging ability may result in severe declines in reproductive output if combined with acute effects over 40%, for instance (see Fig. 5). This underscores the importance of better understanding the effects of exposure to mixtures of toxicants.

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Combined Toxicity and Bioconcentration of Fluoride and Arsenic in African Catfish Clarias gariepinus (Burchell, 1822)

Combined Toxicity and Bioconcentration of Fluoride and Arsenic in African Catfish Clarias gariepinus (Burchell, 1822)

Although numerous studies exist on evaluation of the individual effect of fluoride and arsenic on mammals and fishes, there are no studies related to understanding the potential combined effects of fluoride and arsenic on fish. Cao et al., [53] reported that the concentration of fluoride in the gills and other tissues in C. carpio increased with exposure time and exposure concentration and were in the order of gills > liver > brain > kidney > muscle > intestine. In this study, tissue fluoride content of Clarias gariepinus increased significantly (P<0.01) with increasing water fluoride and arsenic concentration and exposure time. Similar results were obtained by Aguirre-Sierra et al., [54] after exposing white clawed crayfish (A. pallipes) to different concentration of fluoride. Our results also depict BCF values of blood arsenic (0.48 - 0.50), blood fluoride (0.024 - 0.384) and tissue fluoride (0.58 - 0.87), to be in the lower range ie. (<01). However, tissue arsenic was observed to be very high (0.63 - 3.11), indicating that arsenic exceedingly bioaccumulated and biomagnified in the tissues. Data show bioaccumulation of arsenic and fluoride to occur predominantly in liver, it being responsible for detoxification and elimination of toxic elements. Differences in blood fluoride and arsenic concentrations were not significantly different (P>0.05) among the exposure groups.

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Comparative Toxicity of “Tin Free” Self Polishing Copolymer Antifouling Paints and Their Inhibitory Effects on Larval Development of a Non Target Organism

Comparative Toxicity of “Tin Free” Self Polishing Copolymer Antifouling Paints and Their Inhibitory Effects on Larval Development of a Non Target Organism

Booster biocides have been incorporated in antifouling paints to increase the length and functionality of cop- per-based antifouling coating systems, since their usage could provide an interim solution in response to the de- mands for an effective antifouling strategy of TBT replacement [46]. In the formulation of ANTI F booster bio- cide Diuron is included, while MICRON contains the booster biocide Dichlofluanid. Diuron [3-(3,4-dichloro- phenyl)-1,1-dimethylurea] is a substituted urea-based herbicide employed principally for the control of vegeta- tion in non-crop areas since the 1950s, but it is also used as booster biocide in antifouling paints [2]. It has been reported to be relative persistent in seawater [47], considerably stable to hydrolysis [48], and relatively soluble in water [(35 mg/L) (log Kow of 2.8, log Koc of 2.3 - 5.2 and a Kd of 8.9)] [14] [49]. Therefore, it has been suggested that Diuron will be predominantly found in the dissolved phase. The occurrence of Diuron as an anti- fouling agent has been reported in a number of European countries and Japan, but is no longer approved for use in the UK as an active ingredient in antifouling paints on any size of vessel [15]. Biological effects of Diuron in non-target organisms have been demonstrated in the inhibition of hatching of Artemia cysts and molecular binding of the inhibitor to the active site of the hatching enzyme has been proposed [50]. On the other hand, Dichlofluanid (N-dichlorofluoromethylthio-N’,N’-dimethyl-N-phenylsulfamide) is a fungicide, much less so- luble in water (<2 mg/L) with a high octanol/water partition coefficient (log Kow = 3.7), thus it is thought to ra- pidly undergo hydrolysis to form N,N-dimethyl-N’-phenylsulphamide (DMSA) [50] with a half-life in seawater of <20 h [14] [51] and it has been found the most strongly bound biocide in sediments compared to Diuron [52] [53]. Diuron exhibited the least preference for sorptive behavior compared to Dichlofluanid [53]. However, no detectable concentrations of Dichlofluanid have been measured in any of the seawater and sediment samples of Greek marinas since it is known its high hydrolytic and degradation rate [54].

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Lethal temperatures for eggs of Globodera rostochiensis, determined by staining with New Blue R

Lethal temperatures for eggs of Globodera rostochiensis, determined by staining with New Blue R

The description of the use of New Blue R as a stain which differentiates between living and dead nematodes by Shepherd (1962) provided a rapid and simple assay for assessing lethal effects of control treatments, and was used as an assay in the work described in this paper to determine the lethal temperature-time combinations for Globodera rostochiensis, using a nematode population from Prattsburgh, New York.

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