Biochemical identification of putative GABA/benzodiazepine receptors in house fly thorax muscles

[³H]Flunitrazepam ([³H]Flu) was used to identify benzodiazepine binding sites in house fly thorax muscle membranes using a filter assay. [³H]Flu bound to a finite number of sites in a concentration- and time-dependent manner, reaching equilibrium in 10 min. Scatchard plots of the binding indicated a high-affinity site at 0.2 pmol/mg protein (K_d 24.3 nM) and a low-affinity site at 8.2 pmol/mg protein (K_d994nM). Binding of [³H]Flu to the high-affinity binding site was inhibited by several benzodiazepine analogs, with Flu, diazepam, and Ro 5-4864 being more potent than β-CCE, Ro 5-3027, and Ro 5-2180. Clonazepam was least potent in inhibiting [³H]Flu binding. Thus, the drug specificity of these insect muscle benzodiazepine binding sites was quite different from both the mammalian central and peripheral benzodiazepine receptor sites, though closer to the peripheral ones. GABA (γ-aminobutyric acid) and its agonists enhanced the specific binding of [³H]Flu in a dose-dependent manner, and this effect was inhibited with the GABA antagonist bicuculline. The effect was biphasic since at high GABA concentrations this stimulation was reduced. The data suggest that house fly muscles have benzodiazepine receptors, which are coupled allosterically to GABA receptors, analogous to the GABA/benzodiazepine receptors of vertebrates, but with some differences in their drug specificities.     

Downregulation of male-specific cytochrome P450 by profenofos

The health hazards of individual organophosphorus insecticides have been characterized by their acute toxicity, mainly by investigating their cholinesterase inhibition. However, the chronic effects of most of these toxicants on the drug-metabolizing enzymes have not been investigated. Profenofos (O-4-bromo-2-chlorophenyl O-ethyl S-propyl phosphorothioate) is an organophosphorus pesticide widely used in cotton cultivation. In the present study, we investigated the effect of profenofos on male-specific cytochrome P450 (CYP) enzymes in adult Wistar rats. We orally administered 17.8 mg/kg body weight, twice weekly for 65 days. Profenofos downregulated levels of hepatic and testicular CYP2C11 and CYP3A2 mRNA and protein expression. Testicular aromatase (CYP19A) mRNA was decreased in the profenofos-treated rats compared to controls. Overall, the present study suggests that profenofos acts as an endocrine disruptor of male-specific CYP enzymes and affects testosterone concentration, which implicates its deleterious effects on animal or human males chronically exposed to organophosphorus pesticide.     

Drought Tolerance Aspects in Pearl Millet

Different indices for selection of lines grown under low and high water levels were examined from both theoretical and practical standpoints. Pearl millet ( Pennisetum americanum (L.) K. Schum) was planted under a sprinkler irrigation gradient in 1983 and 1984. Equations were developed for drought tolerance for both yield and forage production. Correlation coefficients were developed for yield and yield components.
The equations showed that drought will generally result in decreased productivity of both grain and forage. Grain yield was found to be positively correlated with seed weight and with the number of seeds in the main head, and negatively correlated with plant height under low water level. Dry matter was positively correlated with tiller number.     

Effect of Soil Applied Herbicids on Weed Flora, Yield Attributes, Oil Content and Constituents in Sunflower (Helianthus annuus L.)

Field experiments showed that superior control of the existing weed flora was obtained by applying: alachlor + linuron, alachlor + chloramben and cyanazine. Herbicidal treatments of alachlor, trifluralin, prometryn and oxadiazon were highly effective in controlling dominant weed species. Some herbicidal treatments produced sunflowers with larger head diameter as compared to unweeded check. As a result of suppressed weed interference, alachlor in combination with linuron or chloramben and cyanazine accounted for the highest seed yield values in 1985 and 1986.
Chemical analyses exhibited that sunflower oil content was not affected by weed control applications. Furthermore, oil constituents (oleic, linoleic, steric and palmitic fatty acids) expressed insignificant responses to applied treatments.     

Spinal fluid concentrations of mepivacaine in horses and procaine in cows after thoracolumbar subarachnoid analgesia

The CSF concentrations of mepivacaine in 10 Standardbred horses and of procaine in 10 Holstein cows given the drugs by thoracolumbar subarachnoid injection were determined. Mepivacaine hydrochloride was injected into the horses (502 +/- 60.5 kg) at an average dosage of 30 mg (1.5 ml of 20 mg/ml solution). Analgesia was produced 7.5 +/- 4.3 minutes after injection, extended between spinal cord segments T13 and L3 on both sides of the spinal column, and lasted 47 +/- 18.7 minutes at the T18 dermatome. Procaine hydrochloride was injected into cows (614 +/- 51.5 kg) at a dosage ranging between 75 mg and 100 mg (1.5 ml and 2 ml of 50 mg/ml solution). Analgesia was produced 8.2 +/- 2.0 minutes after injection, extended between spinal cord segments T11 and L4 on both sides of the spinal column, and lasted 47 +/- 17.5 minutes at the T13 dermatome. The critical CSF concentrations of local anesthetics required to eliminate response to pinprick stimulation were 204.4 +/- 90.3 micrograms of mepivacaine/ml in horses and 197.0 +/- 86.1 micrograms of procaine/ml in cows. Average CSF concentrations at 120 minutes after injections were made were 16.8 +/- 15.5 micrograms of mepivacaine/ml and 30.6 +/- 17.1 micrograms of procaine/ml. In in vitro experiments to determine the rates of hydrolysis of mepivacaine and procaine in CSF, significant changes (P greater than 0.05) were not seen in the CSF concentrations of mepivacaine in horses and procaine in cattle after a 120-minute incubation (37 C). The analgesic threshold concentrations of mepivacaine in CSF of horses and procaine in CSF of cows were similar.(ABSTRACT TRUNCATED AT 250 WORDS)     

Untersuchungen zum Einfluß von Konkurrenz auf die Bestandesentwicklung von Sommerraps bei unterschiedlicher Gunst der Umweltbedingungen

Investigations on the effect of competition with regard to the stand development of spring oilseed rape as dependent on environmental conditions
Field experiments were conducted to investigate the frequency distribution in spring oilseed rape as dependent on environmental growing conditions and plant density. As measures for frequency distribution skewness and kurtosis were estimated. The plant character determined was single plant dry matter. To understand the changes in the stand structure, samples were taken at the following developmental stages: rosette, begin of flowering, end of flowering and ripeness (harvest). Plant densities ranged from 60 plants/m², 90 plants/m² till 120 plants/m²
The results show that under unfavourable growing conditions, generally speaking, the values of (positive) skewness and kurtosis increase with the development of the plants; under favourable growing conditions, however, the values of skewness and kurtosis decrease from rosette till harvest.
Under unfavourable growing conditions as well as favourable ones, the values of skewness and kurtosis increase with strengthening of plant competition as consequence of increasing plant density. However, the trend during development and the height of the values as well as the quantitative relationships are strongly controlled by the general growing conditions. Frequency distribution, therefore, is not only a result of plant competition but also of differences in resources due to the general conditions of the location.     

The effects of rapeseed meals from brassica napus varieties and the variety tower on the production and health of laying fowl

1. A diet containing rapeseed meal (200 g/kg) prepared from Brassica napus varieties grown in Britain fed to laying hens consistently depressed egg production when compared with a similar diet containing soyabean meal. Deaths from liver haemorrhage, greatly enlarged thyroid glands and a “ fishy “ taint in eggs from brown hybrids were also associated with the diet containing this rapeseed meal.

2. A similar diet containing rapeseed meal (200 g/kg) prepared from the new Canadian variety Tower did not depress egg production when compared with the soyabean meal diet. Compared with the diet containing the British meal, that containing Tower meal caused fewer deaths from liver haemorrhage and it caused enlarged thyroid glands, but to a much smaller degree. However, it did cause the production of as many tainted eggs as did the diet containing the British meal.     

Effect of adding different levels of caffeine in the extender on some biochemical constituents,enzymatic activities and physical characteristics of chilled and frozen ram semen

Two experiments were carried out to determine the efficiency of supplementation of ram semen extender with caffeine on chilled storage and frozen capacity of spermatozoa. In the first experiment, eighty ejaculates were collected by an artificial vagina from five adult Barki rams, aged 2–3 years and weighted 45.0 ± 2.0 kg throughout the experimental period (January to February 2017). The ejaculates were pooled and diluted (1:10) with tris‐citric egg yolk extender and were split into five groups. Group 1 served as control, whereas groups 2‐5 were supplemented with 0.1, 0.2, 0.3 and 0.4 mM caffeine. All diluted semen specimens were evaluated for physical characteristics immediately after dilution (T₀) and throughout preservation period of 48 hr at 4°C. Simultaneously, oxidative stress and indices such as total antioxidant capacity (TAC), malondialdehyde concentrations (MDA) and alkaline transaminase (AKP) concentrations and value of resazurin reduction test (RRT) were determined. In the second experiment, the raw pooled ejaculates were diluted (1:10) with glycerolated tris‐citric egg yolk extender, receiving the previously mentioned caffeine levels. The post‐thaw assessment of cryopreserved spermatozoa, in all groups, was conducted by a computer‐assisted sperm analysis (CASA) system. The results revealed that adding caffeine to ram semen extender at low (0.1 mM) or medium (0.2 mM) levels had positive impact on both physical characteristics of ram sperm and the enzymatic activities compared to the other semen groups. Caffeine supplementation also enhanced post‐thaw sperm dynamics, which implies its potential as an exogenous antioxidant supplement.