Preovulatory changes in follicular prostaglandins and their role in ovulation in cattle.

Indomethacin (INDO, n = 5) or vehicle (CONTROL, n = 4) was injected into superovulated heifers at 48 and 60 h following a luteolytic cloprostenol injection (0 h). One heifer from each group was ovariectomized (OVX) at 48, 56, 64 and 72 h. The fifth heifer of the INDO group was OVX at 80 h. Blood samples were collected at 0 h, every 2 h between 37 and 47 h, and at the time of each OVX to monitor plasma progesterone (P4) and luteinizing hormone (LH) concentrations. Following each OVX, the number and size of follicles were recorded and the incidence of ovulation determined. Follicular fluid (FF) was aspirated from follicles greater than or equal to 8 mm to determine the concentration of prostaglandins E2 (PGE2) and F2 alpha (PGF2 alpha). The highest PG concentrations were measured in both groups at 24-25 h following the preovulatory LH surge and the PGF2 alpha concentration at this time was significantly greater (p less than 0.01) in the CONTROL group compared to the INDO group. By 35-36 h after the LH surge, 75% (25/34) of the CONTROL follicles had ovulated, whereas there were no ovulations (0/50) on either ovary of the INDO treated heifer. These preliminary results suggest that the preovulatory rise of PGs in FF, particularly PGF2 alpha, is essential for ovulation and that suppression of this rise with indomethacin will inhibit ovulation in heifers.     

Laboratory evaluation of dual-frequency multisensor capacitance probes to monitor soil water and salinity

Real-time information on salinity levels and transport of fertilizers are generally missing from soil profile knowledge bases. A dual-frequency multisensor capacitance probe (MCP) is now commercially available, for sandy soils, to simultaneously monitor volumetric soil water content (VWC) measured as a percentage and salinity as a unitless volumetric ion content (VIC). The objectives of this research were to assess the relationship of salinity and water content with these dual-frequency MCPs under laboratory conditions, and assess its potential for field use in sandy soils of the mid-Atlantic region of the US. Water and salinity studies were conducted in two sand-filled PVC columns, 1.2 m long by 0.25 m ID. Each column was instrumented with ten dual-frequency capacitance sensors and two thermocouple temperature sensors. Four salinity levels were studied in the two columns using 0.5, 1, 2, and 4 dSm⁻¹ NH₄NO₃ solutions. Water, salinity, and temperature readings were continuously recorded at 1-min intervals. The VIC values were found to be primarily qualitative, but combined with real-time VWC measures the probe could still be an important fertigation management tool to provide near-continuous real-time information on fertilizer penetration, spread and subsequent changes during crop growth.

---

An evaluation of the potential of intergeneric gene transfer between Brassica napus and Sinapis arvensis

The possibility of gene transfer between Brassica napus and Sinapis arvensis was evaluated. Six spring-type cultivars of B. napus and four strains of S. arvensis were reciprocally crossed through controlled crosses. No hybrid was yielded from any cross. However, one hybrid with 28 chromosomes was obtained from B. napus×S. arvensis through ovule culture. The hybrid plant was highly sterile and set no seed on open pollination. Two F₂ plants, with 35 and 36 chromosomes respectively, were obtained through self-pollination by hand. Backcross of B. napus produced 23 plants carrying some characteristics of S. arvensis, but backcross to S. arvensis failed to produce a plant. The chromosome counts of the BC₁F₁ plants indicated that gametes with more than nine chromosomes were favoured during the meiosis. The data demonstrated that gene transfer from S. arvensis to B. napus was very difficult under controlled cross and backcross, while to transfer genes from B. napus to S. arvensis would be extremely remote even under the most favorable conditions.     

Parent and harvest year effects on near-infrared reflectance spectroscopic analysis of olive (Olea europaea L.) fruit traits

The influence of parent and harvest year on the determination of oil, moisture, oleic acid, and linoleic acid contents in intact olive fruit was studied by near-infrared spectroscopy (NIRS). Spectral data from 400 to 1700 nm were recorded on 437 fruit samples collected in 1996 and 1997 from seedling plants derived from three different female parents. Partial least squares models were developed using samples for each year and for each female parent separately and were validated against the other groups. Calibration models were accurate enough to predict all constituents in new samples from a different female parent but were not transferable across years. However, a calibration equation of sufficient accuracy was obtained from the combined data set (r values of 0.94, 0.93, 0.84, and 0.88 and RMSECV values of 1.33, 1.88, 4.73, and 2.91 for oil, moisture, oleic acid, and linoleic acid contents, respectively). These results demonstrate the utility of NIRS as a selection tool in olive breeding programs.     

Effect of treatment with levamisole or fenbendazole on primary experimental Dictyocaulus viviparus infection and on resistance in calves

Based on faecal larval counts, respiratory rates and live-weight gains, the anthelmintics levamisole and fenbendazole were equally efficacious against primary infection with Dictyocaulus viviparus in calves. Calves that were treated with levamisole or fenbendazole resisted the live-weight depressing impact of reinfection. Treatment somewhat impaired resistance to establishment of the secondary challenge as determined at necropsy. However, compared with previously uninfected controls, the treated animals harboured significantly fewer D viviparus, showing that they still strongly resisted reinfecting worms becoming established. The animal responses measured did not demonstrate any difference between levamisole and fenbendazole in relation to efficacy or to effect on resistance.     

Detection and identification of bacteria in an isolated system with near-infrared spectroscopy and multivariate analysis

Near-infrared (NIR) transflectance spectra of Listeria innocua FH, Lactococcus lactis, Pseudomonas fluorescens, Pseudomonas mendocina, and Pseudomonas putida suspensions were collected and investigated for their potential use in the identification and classification of bacteria. Unmodified spectral data were transformed (first and second derivative) using the Savitzsky-Golay algorithm. Principal component analysis (PCA), partial least-squares discriminant analysis (PLS2-DA), and soft independent modeling of class analogy (SIMCA) were used in the analysis. Using either full cross-validation or separate calibration and prediction data sets, PLS2 regression classified the five bacterial suspensions with 100% accuracy at species level. At Pseudomonas genus level, PLS2 regression classified the three Pseudomonas species with 100% accuracy. In the case of SIMCA, prediction of an unknown sample set produced correct classification rates of 100% except for L. innocua FH (77%). At genus level, SIMCA produced correct classification rates of 96.7, 100, and 100% for P. fluorescens, P. mendocina, and P. putida, respectively. This successful investigation suggests that NIR spectroscopy can become a useful, rapid, and noninvasive tool for bacterial identification.