Forced unfolding of proteins within cells

To identify cytoskeletal proteins that change conformation or assembly within stressed cells, in situ labeling of sterically shielded cysteines with fluorophores was analyzed by fluorescence imaging, quantitative mass spectrometry, and sequential two-dye labeling. Within red blood cells, shotgun labeling showed that shielded cysteines in the two isoforms of the cytoskeletal protein spectrin were increasingly labeled as a function of shear stress and time, indicative of forced unfolding of specific domains. Within mesenchymal stem cells-as a prototypical adherent cell-nonmuscle myosin IIA and vimentin are just two of the cytoskeletal proteins identified that show differential labeling in tensed versus drug-relaxed cells. Cysteine labeling of proteins within live cells can thus be used to fluorescently map out sites of molecular-scale deformation, and the results also suggest means to colocalize signaling events such as phosphorylation with forced unfolding.     

Use of insect antifeedants against aphid vectors of plant virus disease

The probing and feeding behaviour of aphids can result in uptake of viruses from infected plants and subsequent transmission to healthy plants. It is possible to interfere with virus acquisition and transmission by influencing aphid host-selection and feeding behaviour with antifeedant chemicals. Published work is reviewed and new work is presented in this paper. The two most successful classes of antifeedants against aphids are (a) compounds derived from the aphid alarm pheromone and (b) plant-derived antifeedants such as the sesquiterpene (-)-polygodial. Results with these and other compounds are discussed in terms of antifeedant activity against Myzus persicae, their effects on resistant aphids and the evidence for dec?ease in virus spread by aphids in laboratory and field.     

Some fluorine-containing pheromone analogues

Two analogues of the aphid alarm pheromone (E)-β-farnesene, a trifluorofarnesene and a difluoro-1-norfarnesene, were found to be highly active and were more readily detectable than the parent compound. For (Z)-hexadec-11-enal, a component of some lepidopteran sex attractant pheromones, replacement of the carbonyl oxygen with a difluoromethyl group to give a difluoroheptadecadiene resulted in loss of activity. A trifluoroacetoxyhexadecanolide was a more volatile analogue of the mosquito oviposition pheromone (?)-(5R,6S)-6-acetoxy-5-hexadecanolide and was highly active.     

Complement Titres of Naturally and Artificially Raised Piglets II. Comparison with the Results of Electrophoretic Examinations

Serial serum samples from piglets in one naturally-raised and three artificially-raised litters, 19 animals, were examined by cellulose acetate electrophoresis. The electropherograms of all day-old suckling and colostrum deprived piglets showed five definite bands, the first, third, fourth and fifth corresponding in position to the albumin, alpha-, beta- and gamma-globulin regions for adult pig serum. The second, well-defined band was located between the albumin and main alpha-globulin bands. This component, considered to be alpha₁-globulin or fetuin, was no longer visible as a distinct band in the electrophoretic pattern for sera of three-week old suckling piglets or of five-week old artificially-raised piglets. No consistent relationship was observed between the rate of increase in haemolytic complement titre and the proportional changes in the various categories of serum globulins.     

Diagnostic peritoneal lavage for identification of blastomycosis in a dog with peritoneal involvement

A 6-year-old castrated male Dalmatian was evaluated because of hematemesis. The dog had lived its entire life in South Dakota and Wyoming and had never traveled outside of these states. Results of laboratory testing were compatible with iatrogenic acute renal failure and gastrointestinal tract ulceration secondary to previous nonsteroidal anti-inflammatory drug and corticosteroid administration. Differential diagnoses for clinical signs and laboratory abnormalities that existed prior to these treatments included multisystemic infectious or inflammatory disease and neoplasia. Four-quadrant abdominocentesis did not yield any fluid, but because intra-abdominal disease was still suspected, diagnostic peritoneal lavage was performed. Fluid that was obtained was markedly cellular, and there were numerous extracellular structures with a round to oval shape; a 1-microm-thick, clear-staining capsule; a basophilic interior; and broad-based budding. Organisms were consistent with Blastomyces spp, and fungal culture yielded Blastomyces dermatitidis. Treatment with liposomal amphotericin B and itraconazole was recommended but could not be initiated because of the client's financial constraints. At necropsy, disseminated blastomycosis involving the stomach, small intestines, urinary bladder, omentum, mesentery of the small intestine, and abdominal wall musculature was seen. To our knowledge, peritoneal involvement has not been reported in dogs with blastomycosis, and gastrointestinal tract involvement has only rarely been reported. Findings in this dog suggest that diagnostic peritoneal lavage may be a useful technique in determining the cause of infectious peritonitis when the amount of abdominal fluid is below the limit of detection for abdominocentesis.     

Fluorouracil as a treatment for corneal papilloma in a Malayan tapir

A 26-year-old, wild caught, male Malayan tapir at the Miami Metrozoo with bilateral corneal papillomas was serially immobilized and given subconjunctival injections of fluorouracil. Over the course of 17 weeks five bilateral injections of 25 mg fluorouracil were given. This treatment caused regression of the corneal lesions as evidenced by decreased lesion diameter, decreased corneal vascularity, increased corneal clarity, and improved visual function. No adverse drug effects were observed.     

Accumulation of acaricide resistance mechanisms in Rhipicephalus (Boophilus) microplus (Acari: Ixodidae) populations from New Caledonia Island

Rhipicephalus (Boophilus) microplus has been pesticide-controlled for several decades in the pacific island of New Caledonia. Since 1996, pesticide-control has been based on either deltamethrin (Butox) or amitraz (Taktic) in herds harbouring deltamethrin-resistant ticks. In this island, the first R. microplus deltamethrin- and amitraz-resistances were detected in 1992 and 2003, respectively. Using LPT bioassays, we have undertaken to update data regarding the geographical distribution and the physiological diversity likely to be involved in these resistances. We confirmed that after 17 years of intensive use of deltamethrin, several resistances of moderate levels (<30-fold) have evolved and/or diffused in any part of the island. We also evidenced that amitraz-resistant phenotypes have recently evolved in diverse western tick populations, although none has reached fixation in any tick population yet. According to synergists bioassays, the physiological changes involved in amitraz-resistance in New Caledonia would involve target modification and detoxifying P450 cytochrom oxydase(s). It may also involve detoxifying esterase(s) although this later point will need confirmation on samples bearing higher frequency of resistant phenotypes. Results are discussed with regard to the local evolutionary dynamics of resistance.