Use of fetal skeletal mineralization for prediction of parturition date in cats

OBJECTIVE: To determine the relationship between parturition date and fetal skeletal mineralization detected radiographically in cats. DESIGN: Prospective clinical trial. ANIMALS: 31 queens and their 49 pregnancies. PROCEDURE: Seventeen pregnant queens were radiographed with a computed radiography system every 2 to 3 days from 1 week after pregnancy was identified by abdominal palpation until parturition. Radiographs were evaluated to determine the first identifiable mineralization of 16 bony structures and teeth during each pregnancy. This information was used to establish a table of expected parturition dates on the basis of fetal mineralization. Single radiographs from an additional 32 pregnant cats were evaluated, and predictions of parturition dates were made on the basis of the mineralization table. RESULTS: Mineralization was first detected 25 to 29 days prior to parturition (dpp). Mineralization was determined for the spinal column (22 to 27 dpp), skull (21 to 27 dpp), ribs (20 to 25 dpp), scapula (17 to 24 dpp), humerus (20 to 24 dpp), femur (19 to 23 dpp), radius (15 to 22 dpp), tibia (15 to 21 dpp), ulna (5 to 21 dpp), pelvis (8 to 20 dpp), fibula (0 to 17 dpp), tail (8 to 16 dpp), metacarpals and metatarsals (3 to 14 dpp), phalanges (0 to 11 dpp), calcaneus (0 to 10 dpp), and teeth (1 to 6 dpp). Date of parturition was predictable within 3 days in 75% of cats. CONCLUSIONS AND CLINICAL RELEVANCE: Identification of bony structures in the fetus is useful in estimating the time to parturition in queens.     

Helminthiasis and toxoplasmosis among exotic mammals at the Santiago National Zoo

Parasitologic evaluations of 112 fecal specimens from 292 mammals from the Santiago National Zoo (36 specimens were pooled specimens from greater than or equal to 2 animals) indicated that 51 mammals had protozoa or helminths in their feces. Most of the parasites in the herbivorous species were trichurids and strongylids, whereas most of the parasites in the carnivorous species were ascarids. Coccidia spp and Giardia spp were the most frequently detected protozoans in the mammals evaluated. Of 127 captive mammals serologically evaluated for antibodies against Toxoplasma gondii (indirect hemagglutination test), 35 (27.5%) were positive for T gondii: 7 (46.6%) of 15 carnivores, 24 (25.2%) of 95 artyodactyls, and 4 (22.5%) of 17 nonhuman primates. Antibodies against T gondii also were found in 8 of 10 domestic cats captured within the zoo and in 6 of 13 volunteer zookeepers.     

Photoreceptors in primitive chordates: fine structure, hyperpolarizing receptor potentials, and evolution

Two species of primitive chordates have hyperpolarizing photoreceptor potentials, as vertebrates do. In Salpa the photoreceptive membrane is composed of microvilli, whereas in Amaroucium it is modified from cilia. There appears to be no functional correlation between fine structure of photoreceptive membrane and polarity of response to light.     

The role of B‐type esterases in conferring insecticide resistance in the tobacco whitefly,Bemisia tabaci (Genn)

Separation of non‐specific esterases on electrophoretic gels has played a key role in distinguishing between races or biotypes of the tobacco whitefly, Bemisia tabaci. One intensively staining esterase in particular (termed E_0.14) has assumed significance as a diagnostic of B‐type whiteflies (aka Bemisia argentifolii), despite any knowledge of its biological function. In this study, a whitefly strain (B‐Null) homozygous for a null allele at the E_0.14 locus that had been isolated from a B‐type population was used to demonstrate a significant role for E_0.14 in resistance of B‐type populations to pyrethroids but not to organophosphates (OPs). Bioassays with pyrethroids, following pre‐treatment with sub‐lethal doses of the OP profenofos (to inhibit esterase activity), coupled with metabolism studies with radiolabelled permethrin, supported the conclusion that pyrethroid resistance in a range of B‐type strains expressing E_0.14 was primarily due to increased ester hydrolysis. In the same strains, OP resistance appeared to be predominantly conferred by a modification to the target‐site enzyme acetylcholinesterase. © 2000 Society of Chemical Industry     

新疆B型烟粉虱对不同类型杀虫剂的抗性与分析

应用浸叶法研究了新疆B型烟粉虱对4类不同作用机制杀虫剂的抗药性。结果表明,被测种群对氯氰菊酯和联苯菊酯的抗性指数分别为2100～6200和1000～2200,属于高抗性;对氯化烟酰类杀虫剂产生了低至中等抗性,对吡虫啉的抗性指数为4～86,且抗性指数呈上升趋势,对噻虫嗪的抗性指数为10～22,对啶虫脒的敏感性最佳;对昆虫生长调节剂吡丙醚的抗性指数为22～54;对阿维菌素仍然表现敏感。由此认为,拟除虫菊酯类杀虫剂在新疆已不再适用于烟粉虱的防治,而对受抗药性影响较小的氯化烟酰类杀虫剂(如吡虫啉、噻虫嗪和啶虫脒)、昆虫生长调节剂吡丙醚以及阿维菌素等新型杀虫剂,仍然可以限制性地在不同化合物间交替使用。     

Cloning of an interleukin-3 receptor gene: a member of a distinct receptor gene family

Interleukin-3 (IL-3) binds to its receptor with high and low affinities, induces tyrosine phosphorylation, and promotes the proliferation and differentiation of hematopoietic cells. A binding component of the IL-3 receptor was cloned. Fibroblasts transfected with the complementary DNA bound IL-3 with a low affinity [dissociation constant (Kd) of 17.9 +/- 3.6 nM]. No consensus sequence for a tyrosine kinase was present in the cytoplasmic domain. Thus, additional components are required for a functional high affinity IL-3 receptor. A sequence comparison of the IL-3 receptor with other cytokine receptors (erythropoietin, IL-4, IL-6, and the beta chain IL-2 receptor) revealed a common motif of a distinct receptor gene family.     

Pyrethroid resistance in the tomato red spider mite, Tetranychus evansi, is associated with mutation of the para-type sodium channel

BACKGROUND: The tomato red spider mite, Tetranychus evansi (Baker and Pritchard), is a serious pest of solanaceous crops in many African countries. In this study an investigation has been conducted to establish whether mutation of the para‐type sodium channel underlies pyrethroid resistance in T. evansi strains collected in Southern Malawi. RESULTS: Two T. evansi strains from Malawi showed tolerance to the organophosphate chlorpyrifos and resistance (20–40‐fold) to the pyrethroid bifenthrin, but were susceptible to two contemporary acaricides (abamectin and fenpyroximate) in insecticide bioassays. Cloning of a 3.1 kb fragment (domains IIS5 to IVS5) of the T. evansi para gene from pyrethroid‐resistant and pyrethroid‐susceptible strains revealed a single non‐synonymous mutation in the resistant strains that results in an amino acid substitution (M918T) within the domain II region of the channel. Although novel to mites, this mutation confers high levels of resistance to pyrethroids in several insect species where it has always been associated with another mutation (L1014F). This is the first report of the M918T mutation in the absence of L1014F in any arthropod species. Diagnostic tools were developed that allow sensitive detection of this mutation in individual mites. CONCLUSION: This is the first study of pyrethroid resistance in T. evansi and provides contemporary information for resistance management of this pest in Southern Malawi. Copyright © 2011 Society of Chemical Industry     

Transient expression shows ligand gating and allosteric potentiation of GABAA receptor subunits

Human gamma-aminobutyric acid A (GABAA) receptor subunits were expressed transiently in cultured mammalian cells. This expression system allows the simultaneous characterization of ligand-gated ion channels by electrophysiology and by pharmacology. Thus, coexpression of the alpha and beta subunits of the GABAA receptor generated GABA-gated chloride channels and binding sites for GABAA receptor ligands. Channels consisting of only alpha or beta subunits could also be detected. These homomeric channels formed with reduced efficiencies compared to the heteromeric receptors. Both of these homomeric GABA-responsive channels were potentiated by barbiturate, indicating that sites for both ligand-gating and allosteric potentiation are present on receptors assembled from either subunit.