Determination of an efficient and reliable method for DNA extraction from ticks

Molecular detection of pathogenic microorganisms in ticks is based on DNA amplification of the target pathogen; therefore, extraction of DNA from the tick is a major step. In this study, we compared three different tick DNA extraction protocols based on an enzymatic digestion by proteinase K followed by DNA extraction by a commercial kit (method 1), or on mortar crushing, proteinase K digestion and phenol/chloroform DNA extraction (method 2) and fine crushing with a beads beater, proteinase K digestion and DNA extraction using a commercial kit (method 3). The absence of PCR inhibitors and the DNA quality were evaluated by PCR amplification of the tick mitochondrial 16S rRNA gene using tick-specific primers. With method 1, 23/30 (77%) of the samples were extracted; with method 2, 30/31 (97%) of the samples were extracted and with method 3, 30/30 (100%) of the samples were extracted. DNA extraction efficiency using method 3 is significantly higher than DNA extraction efficiency using method 1 (100% versus 77%, P < 0.05). There was no significant difference between methods 2 and 3. Method 3 was however more adapted to cohort studies than method 2. This technique was validated for cohort tick DNA extraction and applicable to the treatment of small samples such as nymphs and soft ticks with 100% efficiency.     

Impact of Trendelenburg (head down) and reverse Trendelenburg (head up) position on respiratory and cardiovascular function in anaesthetized horses

Objective

To describe the cardiorespiratory effects of a change in table position in anaesthetized horses.

Gonadotropic hormone (GtH) receptors in the testis of the troutSalmo gairdneri: in vitro studies

A particulate fraction obtained from trout testis at the time of spermiation shows saturable binding sites for¹²⁵I-labeled salmon gonadotropin (¹²⁵I-GtH). Non-gonadal tissues (liver, muscle and spleen) did not demonstrate specific¹²⁵I-GtH binding. The tracer's specific activity was determined by the self-displacement method (18 to 30 Ci/g). Maximal specific binding ability of¹²⁵I-GtH varied from 20 to 30% of the labelled ligand added, depending on the hormone preparation. Specific binding of¹²⁵I-GtH to 20 mg of the testis membrane varied from 40 to 85% of the total binding depending on the method of membrane prepratation, and was competitively inhibited by concentrations of unlabelled GtH ranging from ca 1 to 1000 ng/ml of incubate. Gonadotropin of mammalian origin, ovine TSH or salmon prolactin competed only weakly, or not at all, for testicular gonadotropin binding sites (relative potencies s-GtH>>FSH=hCG>s-PRL>bTSH). Scatchard analysis of equilibrium binding studies shows that saturable gonadotropin binding was due to a class of high affinity binding sites (sites I Ka3×10¹⁰ M^–1) and possibly to a second class of lower affinity binding sites (sites II Ka=5 to 14×10⁸ M^–1). The binding capacity of sites I, as measured in enriched membrane preparations, was 45±18 fmoles/g of testis during the period of spermiation. The concentration of GtH required to obtain half maximal displacement of¹²⁵I-GtH in the binding studies was of the same order of magnitude as the apparent ED50 for GtH stimulation of 11-Cetotestosterone (11KT) secretion by trout testesin vitro. Mammalian LH and FSH were 100 to 1000 folds less potent than salmor GtH to increase 11 KT secretion.     

Protein and lysine requirements for maintenance and for tissue accretion in Atlantic salmon (Salmo salar) fry

Available data on the quantitative requirement for lysine (Lys) in different salmonids show much variability. So far, there are very limited data on the maintenance requirements of indispensable (I) amino acids (AA) in fish. In the present study, we determined simultaneously the Lys requirements for maintenance and for protein accretion in Atlantic salmon fry by adapting a protocol established for the piglet. Groups of fish having an initial body weight of 1.5 g were fed for 28 days on isoenergetic diets with increasing nitrogen (N) content supplied by cod meal and a mixture of crystalline AAs (50% of total dietary N). Except the protein-free diet (PF; 0.2% dry matter (DM)), the N content of the other diets was either low (2.9% DM), medium (6.2% DM) or high (8.5% DM). Two types of diets with the same N content were formulated. The AA pattern of three control diets was based on the AA pattern of the cod meal protein. For the other three diets, Lys·HCl was totally omitted from the low-N diet (LPD), and 50% of Lys·HCl was removed from the medium- and high-N diets. After a 28-day feeding trial, carcass N and Lys gains were estimated. N and Lys requirements for maintenance and for growth were calculated regressing daily N or Lys gain against N or Lys intakes. The daily N requirement for growth above maintenance was 3.05 g per g protein gain and for maintenance it was 54 mg kg body weight^− 0.75. From the regression between protein and Lys intake, we calculated that for the accretion of 1 g body protein, the dietary Lys requirement was 152 mg, and that the Lys maintenance requirement for zero N gain was 20 mg kg body weight^− 0.75/day. This last value is higher than the previous estimations obtained for rainbow trout and could be explained by the lower body weight or age of the fish used here.     

Bioactivity of Pelargonium graveolens essential oil and related monoterpenoids against sweet potato whitefly,Bemisia tabaci biotype B

Journal of Pest Science - The sweet potato whitefly, Bemisia tabaci Gennadius biotype B (Hemiptera: Aleyrodidae), causes high economic losses in vegetables, beans, soybeans, peanuts, cotton, and...     

Triticonazole distribution in dressed corn caryopsis and seedlings

A corn seed dressing with the fungicide triticonazole at 760 nmol/seed prevents head smut disease. In resting seeds, the dressing treatment was followed by the penetration of 19% of the product, 9% inside the tegument and 7% inside the pedicel. In growing seedlings, the inner content increased in the storage organs (endosperm + scutellum) as well as in the growing organs. The partition lipophilic phase/water certainly explains the high apparent fungicide concentration progressively reached inside endosperm and scutellum. However, no important transfer of fungicide from these organs to the growing parts seems to occur. It appears therefore that the fungicide transfer from the coating to the roots mostly occurs through dissolution of the product in the surrounding soil water and through root absorption. The efficient fungicide concentration inside the meristem is likely to be obtained during the early stages of development.     

Identification and quantification of cholesterol and cholesterol oxidation products in different types of Iberian hams

Cholesterol and cholesterol oxidation products (COPs) were determined in four different groups of dry-cured Iberian hams, based on the feeding received by pigs and their degree of crossbreeding. After lipid extraction, GC-FID for cholesterol determination and GC-MS to analyze COPs were used. Cholesterol content ranged from 30 to 34 mg/100 g of muscle. Some of the COPs analyzed, such as 7alpha-hydroxycholesterol, 7beta-hydroxycholesterol, and 7-ketocholesterol, were detected in all of the samples. The major cholesterol oxide was 7-ketocholesterol; its concentration ranged from 57 to 71 microg/100 g of muscle. The content of cholesterol and cholesterol oxides in intramuscular lipids of hams was not affected by diet or crossbreeding of Iberian pigs.     

Comparison of the in vitro estrogenic activities of compounds from hops (Humulus lupulus) and red clover (Trifolium pratense)

Because the prevailing form of hormone replacement therapy is associated with the development of cancer in breast and endometrial tissues, alternatives are needed for the management of menopausal symptoms. Formulations of Trifolium pratense L. (red clover) are being used to alleviate menopause-associated hot flashes but have shown mixed results in clinical trials. The strobiles of Humulus lupulusL. (hops) have been reported to contain the prenylflavanone, 8-prenylnaringenin (8-PN), as the most estrogenic constituent, and this was confirmed using an estrogen receptor ligand screening assay utilizing ultrafiltration mass spectrometry. Extracts of hops and red clover and their individual constituents including 8-PN, 6-prenylnaringenin (6-PN), isoxanthohumol (IX), and xanthohumol (XN) from hops and daidzein, formononetin, biochanin A, and genistein from red clover were compared using a variety of in vitro estrogenic assays. The IC50 values for the estrogen receptor alpha and beta binding assays were 15 and 27 microg/mL, respectively, for hops and 18.0 and 2.0 microg/mL, respectively, for the red clover extract. Both of the extracts, genistein, and 8-PN activated the estrogen response element (ERE) in Ishikawa cells while the extracts, biochanin A, genistein, and 8-PN, significantly induced ERE-luciferase expression in MCF-7 cells. Hop and red clover extracts as well as 8-PN up-regulated progesterone receptor (PR) mRNA in the Ishikawa cell line. In the MCF-7 cell line, PR mRNA was significantly up-regulated by the extracts, biochanin A, genistein, 8-PN, and IX. The two extracts had EC50 values of 1.1 and 1.9 microg/mL, respectively, in the alkaline phosphatase induction assay. On the basis of these data, hops and red clover could be attractive for the development as herbal dietary supplements to alleviate menopause-associated symptoms.     

Additional indicator plants for potato spindle tuber virus

Thirteen hybrids ofLycopersicon esculentum Mill. (tomato) and threeLycopersicon species proved susceptible to sap inoculation with the potato spindle tuber virus (PSTV). These hosts showed the characteristic symptoms of epinasty and rugosity of the leaves, vein necrosis of leaves and petioles, and some stem necrosis. No local lesions were observed. These hybrids and species can possibly then be used as additional hosts showing systemic symptoms of the virus in addition to the most commonly used indicator, tomato cultivar Rutgers.