Herbicidal potential of stagonolide, a new phytotoxic nonenolide from Stagonospora cirsii

Stagonospora cirsii is a pathogen of Cirsium arvense, causing necrotic lesions on leaves of this noxious weed. The fungus produced toxic metabolites when grown in liquid culture. A new phytotoxin, named stagonolide, was isolated and characterized as (8R,9R)-8-hydroxy-7-oxo-9-propyl-5-nonen-9-olide by spectroscopic methods. Stagonolide was shown to be a nonhost-specific but selective phytotoxin. Leaves of C. arvense were most sensitive and leaves of tomato and pepper (both Solanaceae) were less sensitive to stagonolide, which was assayed at 5 x 10(-3) M, than other plants. Stagonolide assayed at 5 x 10(-6) M was demonstrated to be a strong inhibitor of root growth in seedlings of C. arvense and some other Asteraceae species. Seedlings growth in wheat and radish was much less affected by the toxin, and seedlings of cucumber were insensitive to it.     

Ein Mischzellenmodell zur Abschätzung der Nitratauswaschung aus landwirtschaftlich genutzten Böden im Winterhalbjahr

A mixing-cell model for estimating nitrate seepage losses from agricultural soils in winter A mixing-cell model is developed with which the leaching of nitrate from agricultural soils in temperate regions during winter can be estimated. The model assumes steady-state flow conditions and takes nitrogen mineralization in the upper soil as well as nitrate deposition from the atmosphere into consideration. Model results are compared with results from a convective-dispersive solute flow model. They show that for common field soil dispersivities mixing-cell model results compare well with those obtained from convective-dispersive theory. With the mixingcell model nitrate leaching calculations were carried out for a variety of soil and climatic conditions. They show that the combined effect of N-mineralization and N-deposition may influence the amount of leached nitrate in winter considerably, especially in regions with light soils and high seepage rates. It is shown that the model can be used to derive late fall site-specific upper limits for soil mineral nitrogen for groundwater protection purposes. Such upper limits should reflect the crop-specific rate of N-mineralization that can be expected during winter.     

New alternative method of benzo[a]pyrene extractionfrom soils and its approbation in soil under technogenic pressure

Purpose

The optimization of benzo[a]pyrene extraction conditions by subcritical water extraction method from soils is the purpose of the research. The optimal conditions for benzo[a]pyrene recovery are 30-min extraction by water in a special steel cartridge at 250 °C and 100 atm.

Materials and methods

Studies were conducted on the soils of monitoring plots subjected to Novocherkassk Power Station emissions. Monitoring plots were established at different distances from the Novocherkassk Power Station (NPS; 1.0–20.0 km).

Results and discussion

It was shown that the use of water in subcritical state as a solvent for benzo[a]pyrene extraction from soil allows to avoid large volumes of organic solvents and to decrease the time of sample preparation. It is shown that the maximum benzo[a]pyrene maintenance was observed in soils of the monitoring plots located most close (to 5 km) to a pollution source in the area of the prevailing direction of a wind rose. Dynamics of pollutant accumulation in soils depend on number of Novocherkassk state district power station emissions.

Conclusions

The method of benzo[a]pyrene subcritical water extraction from soil was developed and approbated during long-term monitoring researches of technogenic polluted territories. The optimum conditions for benzo[a]pyrene extraction from soil have been determined: the soil is treating by subcritical water at 250 °C and 100 atm of pressure for 30 min. Trends in the accumulation of benzo[a]pyrene in soil zones of the thermal power plant influence have been researched over a 5-year period of monitoring observations by subcritical water extraction method. Benzo[a]pyrene accumulation in soils depends on the technogenic emissions to the atmosphere from Novocherkassk power station and on the soil physical and chemical properties.

     

Efficiency of breeding and utilisation of the gene pool in commercial pig production

The problems of increasing the efficiency of improvement by selection are considered, together with the methods of increasing the efficiency with which the selected stock is utilised on large industrial complexes. An experiment has shown that breeding on the basis of boar progeny testing and gilt performance testing gives improvements of 9 g for daily gain and 0.04 SFU for feed conversion ratio per generation. These values exceeded the results of experiments where selection was based solely on the performance test.The efficient utilisation of the gene pool in commercial production is achieved by providing boards and gilts from nucleus sources as replacements for the large industrial complex whilst utilising hybridisation programmes. Gilts brought in in this way are more productive than those raised on the complex itself.The sons of boars selected by progeny test at a testing unit are subjected to progeny testing under the conditions of the commercial complex, particularly to study the effects of interaction on crossbreeding. Boars are tested for quantity, quality and stability of production. Each character is evaluated by an index score and the sum of the index scores is the overall estimation of breeding value. Such an estimation allows the selection of the best boars in terms of the productivity of their offspring under the conditions of the given intensive commercial complex.     

Evaluation of an Artificial Insemination Programme in a Seasonal Breeding Dairy System through Milk Progesterone

In order to evaluate an artificial insemination programme and reproductive efficiency of dairy herds in Uruguay, a survey was conducted with five dairy farms, utilizing a total of 768 lactating Holstein cows. Precision of oestrous detection was assessed by one milk progesterone sample taken on day of breeding and was 11.1%. Two additional samples taken at day 10 and 23 were used to confirm ovulation and early pregnancy. Accuracy of pregnancy estimation by milk progesterone was 70.4%. Reproductive efficiency was determined by the analysis of records. Average intervals from calving to first service were 101 days and to conception 132 days and these were affected by parity, body weight and body condition at calving, but not at breeding, or by milk production. Oestrous detection rates and pregnancy rates were 37.5 and 15.6%, respectively. It was concluded that losses in reproductive efficiency in dairy farms of Uruguay in a seasonal artificial insemination programme were mainly due to unobserved heats, rather than incorrect oestrous detection.     

Severe seizures associated with traumatic brain injury managed by controlled hypothermia,pharmacologic coma,and mechanical ventilation in a dog

Objective – To describe the management and outcome of a dog presenting with intractable seizures associated with traumatic brain injury. Case Summary – A spayed female Wheaten Terrier was presented to an emergency clinic with neurologic deficits (modified Glasgow coma scale of 10) shortly after a road traffic accident. Seizures were uncontrolled despite aggressive pharmacologic intervention. Controlled hypothermia to achieve a rectal temperature of 33–35°C (91.4–95°F) was initiated as a protective measure to reduce intracranial pressure and cerebral metabolic rate, and to assist with seizure control. Intubation and mechanical ventilation were required to protect the airway and manage hypercapnia associated with hypoventilation. The patient went on to make a full recovery, although behavioral changes were noted by the owners for an 8‐week period following injury. New or Unique Information Provided – To the author's knowledge, this is the first instance of therapeutic hypothermia reported in the veterinary literature. A short review of this treatment modality is provided.