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PubMed2002

Effects of iron sulfate dosage on the water flea (Daphnia magna Straus) and early development of carp (Cyprinus carpio L.).

Adult water fleas, Daphnia magna Straus, and the early life stages of carp, Cyprinus carpio L., were exposed to river water near an iron sulfate dosage installation to determine the effects of phosphate precipitation with iron(II)sulfate. Tests were conducted during two consecutive dosage periods of 3,000 and 5,000 kg/day iron sulfate (520 and 620 microg/L total Fe respectively) at the dosage site and at a reference site (60 microg/L total Fe) further downstream. Though survival remained unaffected, the filter-feeding D. magna accumulated iron and other metals at the dosage site. Viability of offspring was strongly reduced at the highest dose of iron sulfate compared to the lower dose and the reference site. Specific staining of microscopic sections revealed a strong accumulation of iron(III) in the digestive tract. The egg membranes of the carp embryos accumulated not only substantial amounts of iron but also other metals, including cadmium and aluminium. Hardly any of the metals passed the egg membranes and reached the embryos. After hatching the accumulation of cadmium by the larvae increased rapidly and iron levels were elevated at the highest dose of iron sulfate, parallel with the onset of exogenous feeding. Iron(III) particles were observed in the intestines at histological examination. In addition, at 620 microg/L total Fe a strong increase in whole-body levels of the stress hormone cortisol was observed in the carp larvae, indicating a physiological response to adverse conditions. The results indicate that the rapid oxidation of free Fe2+ into iron(III) forms and the precipitation of iron(III) into larger particles resulted in a low acute toxicity of the river water directly at the iron sulfate dosage site. The observed chronic and sublethal effects at the dosage site probably resulted from the intestinal uptake of iron(III) and other toxic metals associated with the food particles. However, these effects could no longer be observed at the reference site, 9 km downstream from the dosage site.

Animals↗
PubMed2003

Uptake and metabolism of pyrrolizidine alkaloids in Longitarsus flea beetles (Coleoptera: Chrysomelidae) adapted and non-adapted to alkaloid-containing host plants.

Several Longitarsus flea beetle species sequester pyrrolizidine alkaloids acquired from their Asteraceae and Boraginaceae host plants. We carried out feeding and injection experiments using radioactively labeled pyrrolizidine alkaloids to investigate the physiological mechanisms of uptake, metabolism and storage of alkaloids in adult beetles. We examined six Longitarsus species belonging to different phylogenetic clades in a comparative approach. All species that accepted pyrrolizidine alkaloids in a preceding food choice study showed the ability both to store pyrrolizidine alkaloid N-oxides and to metabolize tertiary pyrrolizidine alkaloids into their N-oxides. Regardless of whether the beetles' natural host plants contain pyrrolizidine alkaloids or not, these species were found to possess an oxidizing enzyme. This oxygenase appears to be specific to pyrrolizidine alkaloids: [3H]Atropine and [14C]nicotine, two alkaloids not related to pyrrolizidine alkaloids, were neither stored nor N-oxidized by any of the tested species. One species, L. australis, that strictly avoids pyrrolizidine alkaloids behaviorally, exhibited a lack of adaptations to pyrrolizidine alkaloids on a physiological level as well. After injection of tertiary [14C]senecionine, beetles of this species neither N-oxidized nor stored the compounds, in contrast to L. jacobaeae, an adapted species that underwent the same treatment. L. jacobaeae demonstrated the same efficiency in N-oxidation and storage when fed or injected with tertiary [14C]senecionine.

Animals↗
PubMed2001

Orientation of nonrandomly segregating sex chromosomes in spermatocytes of the flea beetle, Alagoasa bicolor L.

In males of the flea beetle, Alagoasa bicolor L., spermatocytes have two achiasmate sex chromosomes, X and Y, each of which is approximately five times larger than the ten pairs of chiasmate autosomes. At metaphase I, these univalent sex chromosomes are located on a spindle domain separated from the autosomal spindle domain by a sheath of mitochondria. A single centriole pair is located at each pole of the spindle. In prometaphase I, each sex chromosome appears to maintain an attachment to both spindle poles via kinetochore microtubules (i.e., amphitelic orientation). Before anaphase I, this orientation changes to the syntelic orientation (both sister kinetochores connected to the same pole), perhaps by the release of microtubule attachments from the more distant pole by each of the chromosomes. The syntelic orientation just prior to anaphase I leaves each sex chromosome attached to the nearest pole via kinetochore microtubules, ensuring nonrandom segregation. As the sex chromosomes reorient, the autosomes follow in a sequential manner, starting with the bivalent closest to the sex spindle domain. We report here data that shed new light on the mechanism of this exceptional meiotic chromosome behavior.

Animals↗
PubMed2002

A survey of bacterial diversity in ticks, lice and fleas from Australia.

We isolated bacteria from ticks, lice and fleas. Partial small subunit rRNA sequences were obtained for each isolate and the closest matches in the FastA database were determined. These bacteria were mostly Gram-positive (Firmicutes), although representatives from the Proteobacteria (alpha, beta, gamma subdivisions) and CFB group were also isolated. Most of the isolates we found were from genera that were present in most of the ectoparasites studied, but a few genera were restricted to one species of ectoparasite. The most commonly isolated genera were Stenotrophomonas, Staphylococcus, Pseudomonas, Acinetobacter and Bacillus. Species of Bacillus and Proteus, which have biopesticide potential, were found in some of these ectoparasites. Overall, the communities of bacteria were similar to those found in other studies of parasitic arthropods.

Animals↗
PubMed2005

Extract of the seeds of the plant Vitex agnus castus proven to be highly efficacious as a repellent against ticks, fleas, mosquitoes and biting flies.

About 70 plant extracts were tested for their ability to repel the attacks of blood-sucking arthropods. It was found that a CO2 extract of the seeds of the Mediterranean plant Vitex agnus castus (monk's pepper) can be used as a spray to keep away especially Ixodes ricinus and Rhipicephalus sanguineus ticks from animals and humans for at least 6 h. In addition mosquitoes, biting flies and fleas are also repelled for about 6 h.

Animals↗
PubMed2006

Genetic variability of Tunga penetrans (Siphonaptera, Tungidae) sand fleas across South America and Africa.

Tunga penetrans is a widely distributed sand flea, infecting men and domestic animals. It originated in South America, but it is now also endemic of Sub-Saharan Africa due to a recent accidental introduction. Previous genetic analyses indicated a very limited variability in the Ecuadorian populations; on the other hand, samples from Madagascar resulted to be genetically isolated. To better examine the genetic variability of T. penetrans, a wider sampling was analysed for mitochondrial (cytochrome oxidase II) and nuclear (ribosomal internal transcribed spacer [ITS] 2) DNA sequences. The mitochondrial marker confirms the low genetic variability, with few haplotypes characterizing the majority of individuals from different populations. Haplotype distribution is in agreement with a recent colonization of Africa and with a rapid spreading across this continent. Moreover, a consistent gene flow between the Pacific and Atlantic South American populations emerges, possibly due to human and/or animal cross-Andean dispersal. On the other hand, the ITS2 marker depicts a sharply diverging pattern with samples collected in Ecuador unequivocally distinguished from the Brazilian and African ones. On the whole, taking into account also the molecular features of the marker used, data here presented are better interpreted in the light of a high dispersal ability of T. penetrans, probably reducing the phylogeographic signal.

Africa↗
PubMed2005

Responses of flea beetle Phyllotreta cruciferae to synthetic aggregation pheromone components and host plant volatiles in field trials.

Male-specific compounds, previously identified from Phyllotreta cruciferae and synthesized or isolated from natural sources, attracted both sexes of the beetle in field trials and therefore function as components of a male-produced aggregation pheromone. Six field experiments of 7 to 10 d duration each were conducted over 2 yr using modified boll weevil traps and two doses of pheromone. Treatments containing two doses of allyl isothiocyanate (AITC), a breakdown product of glucosinolates in Brassica napus L., a host plant of the beetles, were included in the study. A dose response was observed for both the pheromone components and AITC, and combinations of the pheromone and AITC generally attracted greater numbers of flea beetles than did either component itself. This increased attraction to a combination of beetle-produced compounds and host odors has not been previously demonstrated in halticine beetles and could help explain patterns of movement by P. cruciferae into field crops.

Animals↗
PubMed1984

Biochemical and morphological comparison of microsomal preparations from rat, quail, trout, mussel, and water flea.

Differential centrifugation methods already in use were applied to purify rat, quail, and trout liver microsomes and modified as necessary to purify microsomes from mussel digestive gland and whole water flea. All these microsomal preparations were comparatively characterized with respect to protein and RNA content, levels of markers of subcellular contaminants, ultrastructural morphology, differential spectra of cytochromes P-450 and b5, monoxygenase activity, and in vitro metabolism of p-dichlorobenzene. Yields of microsomal proteins of the tested organisms differed widely, with mussel showing the lowest yield. Very low levels of nuclear and mitochondrial contaminants were detected in all microsomal preparations, but cell membrane contaminants were clearly present in most preparations. Daphnia microsomes were significantly contaminated by plasma membranes, and hepatopancreas microsomes contained significant amounts of partially disrupted secretory granules and plasma membrane. From a qualitative standpoint differential spectra of cytochrome b5 were very similar for all the preparations, whereas cytochrome P-450 spectra were largely dependent on the microsomal preparation as well as on the assay method used. The content of cytochrome P-450 was highest for rat liver microsomes and very low or absent in Daphnia and mussel preparations; the range of cytochrome b5 contents was much narrower. Significant differences were observed among monoxygenase activities of the different preparations. In Daphnia and mussel microsomes, aniline hydroxylase was absent and benzo[a]pyrene hydroxylase activity was much lower than in rat and quail microsomes. Benzo[a]pyrene hydroxylase activity of trout liver microsomes was similar to that of rat and quail microsomes, whereas hydroxylation of substrates which in rat liver are preferentially metabolized by phenobarbital-inducible forms of cytochrome P-450 was much lower in trout microsomes.

Animals↗
PubMed1987

Aspects of the immunopathogenesis of flea allergy dermatitis in dogs.

This paper reviews the current data on the nature of the allergen(s) of the cat flea, Ctenocephalides felis and on some of the factors that determine the development and maintenance of the allergic state. The role of immediate hypersensitivity mediated by IgE, delayed hypersensitivity and of cutaneous basophil hypersensitivity in the immunopathogenesis is discussed. Finally, data on the nature of immunologic non-reactivity is presented and the prospects for therapeutic immunologic intervention discussed.

Allergens↗
PubMed1996

Ctenocephalides felis flea infestation in horses.

The horses were in two stables: in the first stable they were kept together with sheep and in the second stable they were kept together with goats. All horses in both stables were diagnosed as being infested with the cat flea Ctenocephalides felis felis. Foals were severely infested, whereas adult horses were only moderately infested.

Aging↗
PubMed1988

Pyrethrin poisoning from commercial-strength flea and tick spray.

A case of acute poisoning followed inhalation and cutaneous exposure to an over-the-counter flea and tick insecticide containing 0.15% pyrethrins. A self-limited syndrome of cutaneous paresthesias, upper respiratory tract irritation, dyspnea with productive cough, and repetitive vomiting and diarrhea occurred. The patient recovered uneventfully with conservative therapy. A review of the pharmacology and toxicity of pyrethrins and related products is discussed, as well as management of pyrethrin poisoning.

Acute Disease↗
PubMed2005

The screening of chemicals for juvenoid-related endocrine activity using the water flea Daphnia magna.

U.S. Environmental Protection Agency is charged with developing a screening and testing paradigm for detecting endocrine toxicity of chemicals that are subject to regulation under the Food Quality Protection and the Safe Drinking Water Acts. In this study, we developed and evaluated a screening assay that could be employed to detect juvenoid-related endocrine-modulating activity in an invertebrate species. Juvenoid activity, anti-juvenoid activity, and juvenoid potentiator activity of chemicals was assessed using the water flea Daphnia magna. Male sex determination is under the regulatory control of juvenoid hormone, presumably methyl farnesoate, and this endpoint was used to detect juvenoid modulating activity of chemicals. Eighteen chemicals were evaluated for juvenoid agonist activity. Positive responses were detected with the juvenoid hormones methyl farnesoate and juvenile hormone III along with the insect growth regulating insecticides pyriproxyfen, fenoxycarb, and methoprene. Weak juvenoid activity also was detected with the cyclodiene insecticide dieldrin. Assays performed repetitively with compounds that gave either strong positive, weak positive, or negative response were 100% consistent indicating that the assay is not prone to false positive or negative responses. Five candidate chemicals were evaluated for anti-juvenoid activity and none registered positive. Four chemicals (all trans-retinoic acid, methoprene, kinoprene, bisphenol A) also were evaluated for their ability to potentiate the activity of methyl farnesoate. All registered positive. Results demonstrate that an in vivo assay with a crustacean species customarily employed in toxicity testing can be used to effectively screen chemicals for juvenoid-modulating activity.

Animals↗
PubMedDate not supplied

Wolbachia infection in the newly described Ecuadorian sand flea, Tunga trimamillata.

Wolbachia pipientis is an intracellular endosymbiont producing reproductive alterations in its hosts. This bacterium have been reported in many arthropods and nematodes. By PCR amplification and sequencing of the 16S rDNA and ftsZ genes we have identified a Wolbachia strain in the newly described sand-flea, Tunga trimamillata. Prevalence of this endosymbiont in the 26 individuals screened is equal to 35%. Sympatric and allopatric specimens of the related species Tunga penetrans were also analysed, but in contrast to literature data, Wolbachia appears absent in the presently analysed 24 specimens. Field studies evidence a female-biased sex-ratio in T. trimamillata, suggesting that Wolbachia may cause sex-ratio distortion in this species. By means of BLAST search and phylogenetic analysis we found that the Wolbachia strain from T. trimamillata pertains to the arthropod-infecting Wolbachia; this strain is highly differentiated from the Wolbachia strain of T. penetrans described in literature.

Animals↗
PubMed2005

Exploring embryonic germ line development in the water flea, Daphnia magna, by zinc-finger-containing VASA as a marker.

VASA is an ATP-dependent RNA helicase belonging to the DEAD-box family that, in many organisms, is specifically expressed in germ line cells throughout the life cycle, making it a powerful molecular marker to study germ line development. To obtain further information on germ line development in crustaceans, we cloned VASA cDNAs from three branchiopod species: water fleas Daphnia magna and Moina macrocopa, and brine shrimp Artemia franciscana. RNA helicase domains in branchiopod VASA were highly conserved among arthropod classes. However, N-terminal RNA-binding domains in branchiopod VASA were highly diverged and, unlike other arthropod VASA reported so far, possessed repeats of retroviral-type zinc finger (CCHC) motifs. Raising specific antibodies against Daphnia VASA revealed that the primordial germ cells (PGCs) in this organism segregate at a very early cleavage stage of embryogenesis in parthenogenetic and sexual eggs. Clusters of PGCs then start to migrate inside the embryo and finally settle at both sides of the intestine, the site of future gonad development. RNA analyses suggested that maternally supplied vasa mRNA was responsible for early VASA expression, while zygotic expression started during blastodermal stage of development.

Amino Acid Motifs↗
PubMed2006

Water-flea males from the netherworld.

Simple treatments with hormones could unlock the expression of complex phenotypes not known to occur in nature. Using this method, Kim et al. recently obtained males from all-female populations of water fleas. The novel characters revealed by this work can be used in taxonomic identification and phylogenetic inference. Additionally, these "resurrected" males offer insights into the conservation of traits that are not exposed to natural selection.

Animals↗
PubMed2006

World Association for the Advancement of Veterinary Parasitology (W.A.A.V.P.) guidelines for evaluating the efficacy of parasiticides for the treatment, prevention and control of flea and tick infestation on dogs and cats.

These guidelines are intended to assist the planning and conduct of laboratory and clinical studies to assess the efficacy of ectoparasiticides applied to dogs or cats for the purpose of treating, preventing and controlling flea and tick infestations. The term ectoparasiticide includes insecticidal and acaricidal compounds, as well as insect growth regulators. The range of biological activities accruing from animal treatment that are considered include: repellency and anti-feeding effects, knockdown, speed of kill, immediate and persistent lethal effects, and interference with egg fertility and subsequent development of off-host life cycle stages. Information is provided on the selection of animals, dose determination, dose confirmation and field studies, record keeping, interpretation of results and animal welfare. These guidelines are also intended to assist registration authorities involved in the approval and registration of new parasiticides, and to facilitate the worldwide adoption of harmonized procedures.

Animals↗
PubMed2001

Selective sequestration of iridoid glycosides from their host plants in Longitarsus flea beetles.

We investigated in eight species of the flea beetles genus Longitarsus (Coleoptera, Chrysomelidae) whether the beetles take up iridoid glycosides from their host plants of the Lamiaceae, Plantaginaceae, and Scrophulariaceae. Five of the beetle species, L. australis, L. lewisii, L. melanocephalus, L. nigrofasciatus, and L. tabidus, could be shown to sequester iridoid glycosides in concentrations between 0.40 and 1.55% of their dry weight. Eight different iridoid glycosides, acetylharpagide, ajugol, aucubin, catalpol, 8-epi-loganic acid, gardoside, geniposidic acid, and harpagide could be identified in the host plants, yet only aucubin and catalpol are sequestered by the beetles. No iridoid glycosides could be detected in the beetles if neither aucubin nor catalpol were present in the host plant, as in L. minusculus on Stachys recta (acetylharpagide only) and in L. salviae on Salvia pratensis (no iridoid glycosides). In one beetle species, L. luridus, we could not detect any iridoid glycosides although its field host, Plantago lanceolata, had considerable amounts of aucubin and catalpol plus two further iridoids. The five sequestering Longitarsus species differ in their capacity to store the compounds and in their affinity for catalpol relative to aucubin.

Journal Article↗
PubMed2001

Preliminary characterisation of esterase and platelet-activating factor (PAF)-acetylhydrolase activities from cat flea (Ctenocephalides felis) salivary glands.

Naphthyl esterase and platelet-activating factor (PAF)-acetylhydrolase activities were detected in the salivary glands of the cat flea, Ctenocephalides felis. Salivary naphthyl esterase activity is disgorged during exploratory probing. Whole extracts of salivary glands contain esterase activity against the short-chain naphthyl esters alpha-naphthyl acetate (approximately 210pmol/min/gland pair; 10.0micromol/min/mg specific activity; K(m) approximately 59microM) and beta-naphthyl acetate (approximately 110pmol/min/gland pair; 5.2micromol/min/mg specific activity; K(m) approximately 132microM). Salivary gland extracts have PAF-acetylhydrolase activity (approximately 5pmol/min/gland pair; 0.24micromol/min/mg specific activity) but do not have detectable acetylcholinesterase activity. Native-PAGE and IEF resolve three and six salivary gland naphthyl esterase bands, respectively, and both patterns are different from carcass esterases. Salivary gland naphthyl esterase activity binds reversibly to Concanavalin A, and enzymatic deglycosylation with glycopeptidase F produced a new, fast-migrating salivary gland naphthyl esterase band on Native-PAGE. Renaturation of esterase activity after SDS-PAGE gave approximately 56kDa, approximately 57kDa and approximately 58kDa naphthyl-esterase-positive bands. On gel filtration naphthyl esterase and PAF-acetylhydrolase activities co-elute as a single peak with an apparent molecular weight of approximately 59kDa. This partially purified pool of enzyme had esterase activity against a series of short-chain alpha- and beta-naphthyl esters. The heterogeneity of salivary gland esterases, their relationship to PAF-acetylhydrolase, and the possible physiological functions of salivary gland PAF-acetylhydrolase activity are discussed.

1-Alkyl-2-acetylglycerophosphocholine Esterase↗