A.H. El‐Sebae

Effects of edifenphos and glyphosate on the immune response and protein biosynthesis of bolti fish (Tilapia nilotica )

The effects of 1/1000 field recommended concentration of the organophosphorus compounds; edifenphos and glyphosate on the immune response and protein contents were investigated after different time intervals. The cell mediated immune response assessed by proliferative response of splenocytes to mitogens; phytohemagglutinin (PHA) and concanavalin A (Con A) for T cell and lipopolysaccharide (LPS) for B cell decreased significantly in tems of the level of stimulation index in the treated fish and reached maximal depression after 4 weeks. Humoral immunity assessed as splenic antibody plaque forming cells (PFC) measured after 5 days in vitro immunization to sheep erythrocytes (SRBCs) were suppressed in a concentration dependent pattern by the two compounds. The estimated ED50 for the PFC/10(6) cells of edifenphos and glyphosate were 1.48 x 10(-2) uM and 1.65 x 10(-2) uM respectively. The data also showed that serum antibody titres in the treated fish were decreased in a time dependent manner. The total protein content of serum treated with the two pesticides was decreased after different time periods compared with control. The blood serum of treated and untreated Tilapia nilotica were analyzed electrophoretically for protein components and the percentage of proteins in each fraction was determined.

Assessment of lead toxicity in traffic controllers of Alexandria, Egypt, road intersections

Blood lead level (BPbL) was determined in forty-five traffic controllers working on Alexandria road intersections. Central nervous system dysfunction in the subjects studied was investigated by means of performance tests. Biochemical indicators related to lead exposure such as delta-aminolevulinic acid dehydratase and hemoglobin in their blood were also determined. Results indicated that most of the subjects studied have a comparably high BPbL. They also showed significantly poorer performance scores than that obtained in a previous study with a group of textile workers of the same age and educational levels. The mean of the BPbL in the traffic controllers was found to be 68.28 +/- 13.22 micrograms/dl. This is a very high level compared to an acceptable level of 30.00 micrograms/dl. All neurobehavioral symptoms demonstrated in the traffic controllers could be attributed to a high level of lead exposure.

In-vivo interaction of some organophosphorus insecticides with different biochemical targets in white rats.

A comparative study between five organophosphorus insecticides: Leptophos, EPN, Cyanofenphos, Chlorpyrifos and Diazinon, was carried out for acute oral toxicity to white rats and for their in vivo interaction at 1/10th of LD50 doses with the activity of six serum enzymes after 4 wks from oral administration. Leptophos, Chlorpyrifos and diazinon exerted significant inhibition particularly to glutamic oxaloacetic transaminase (GOT), glutamic pyruvic transaminase (GPT), glutamyltransferase (GT) and lactate dehydrogenase (LDH). Adding ascorbic acid in the diet at 0.5% enhanced the acute oral toxicity of leptophos, chlorpyrifos and diazinon. For all the compounds, presence of ascorbic acid protected a number of the monitored serum enzymes from being inhibited except for leptophos. Ascorbic acid caused hypoglycemia with sublethal doses of leptophos, chlorpyrifos, and diazinon. The synergist piperonyl butoxide alone at 750 mg/kg dose inhibited the activity of the six serum enzymes. Presence of ascorbic acid in the diet intensified the inhibitory effect of piperonyl butoxide to all enzymes except for GOT.

Biochemical interaction of six op delayed neurotoxicants with several neurotargets

Five organophosphorous insecticides: Leptophos, EPN, Cyanofenphos, trichloronate and salithion proved to cause irreversible ataxia not only to chicken but also to mice and sheep. TOCP was included as a reference. Cyanofenphos blocked the catecholamine B-receptor binding activity with 3H-norepinephrine at a level similar to that of the specific inhibitor propranolol in the mouse heart preparation. In the lamb heart preparation, the B-receptor was more sensitive to Leptophos, salithion and TOCP than to propranolol. The six compounds and their oxons were screened for their in-vitro inhibition to monamine oxidase (MAO), acetyl cholinesterase (AChE) and neurotoxic esterase (NTE) in the brain of either mouse, lamb or chicken. It is believed that their AChE inhibition stands for their acute toxicity, while NTE inhibition is responsible for their paralytic ataxia.

Gossypol as an inducer or inhibitor in spodoftera littoralis larvae

Gossypol occurs naturally in the pigment glands in cotton. It has a role in protecting cotton plants from insect pests such as bollworms, yet it was not toxic to the cotton leafworm larvae Spodoptera littoralis up to 2-5% concentration in artificial diet or at 125 micrograms/ larva by topical application. The compound inhibited protease and lipid peroxidase activities in larvae with in vitro I50 values of 1.5 X 10(-3)M, and 4.4 X 10(-4)M respectively. When gossypol was fed to Spodoptera larvae, it stimulated the microsomal N-demethylase in vitro. This inductive effect was time-dependent similar to that of phenobarbital. Gossypol stimulates ATPase at lower concentrations and inhibited it at higher concentrations. The I50 for mitochondrial ATPase was 1.7 X 10(-4)M, while the corresponding values for DDT and fenvalerate were 1.1 X 10(-4)M and 7.0 X 10(-4)M respectively. Gossypol at 1.5% concentration in the diet reduced the larval weight to 50% of the control within two days, and increased the duration of each larval stage. The number of eggs and their hatchability was seriously decreased in larvae treated for three consecutive generations. Such an effect can be attributed to the ability of gossypol to interfere with protein bio-synthesis.

A direct method to assay neurotoxic esterase activity

A direct photometric method for assaying neurotoxic esterase (NTE) activity of chicken brain microsomal preparation has been developed using 4-nitrophenyl esters as substrates. Paired samples of the microsomal preparation were preincubated for 20 min with paraoxon plus either (a) buffer or (b) mipafox before addition of substrate. The initial rate of NTE activity was directly recorded at 410 nm by matching the content of tube (a) against tube (b) after addition of the substrate to both of them. The 4-nitrophenyl esters of propionic, butyric, valeric, lauric, capric and caproic acids were tested as substrates. Results indicated that 4-nitrophenyl valerate and caproate, respectively, are the most hydrolyzable substrates for NTE with this method; its also enables detailed kinetic studies of NTE to be made. The Michaelis constant (Km) for the hydrolysis of 4-nitrophenyl valerate by NTe was found to be 5.55 . 10(-5) M.

In vitro effect of profenofos, fenvalerate and dimilin on protein and RNA biosynthesis by rabbit liver and muscle tissues

The present study was carried out to investigate the effect of Curacron (profenofos), Sumicidin (fenvalerate) and Dimilin (difluobenzuron) on the in vitro rate of protein and RNA synthesis by rabbit liver and muscle tissues. The synthesis of protein and RNA were significantly stimulated in the liver and inhibited in the muscle by graded doses of these insecticides. Profenofos showed maximum effect on protein synthesis in both tissues at a dose of 0.2 microgram/mL, while the maximum effect on RNA synthesis occurred at 0.2 microgram/mL, while the maximum effect on RNA synthesis occurred at 0.2 microgram mL in the liver and at 2 micrograms/mL in the muscle. Fenvalerate caused maximum stimulation in both liver protein and RNA synthesis at a dose of 2 micrograms/mL, and maximum inhibition in the muscle at 10 and 0.2 micrograms/mL for protein and RNA synthesis respectively. The maximum effect of Dimilin on both tissues was reached at 5 micrograms/mL for protein synthesis and at 0.2 microgram/mL for RNA synthesis. The effect of Dimilin on RNA synthesis was more pronounced in both tissues than its effect on protein synthesis, but this trend was reversed in the case of profenofos and fenvalerate. Present data also showed antagonism between these insecticides on the rate of protein and RNA synthesis.

Biochemical effects of some organo‐phosphorus insecticides on new targets in white rats

The three S-n-propyl phosphates and phosphothioates: RH 218, profenofos and prothiophos were compared with fenitrothion in their potential as inhibitors of rat liver and brain AChE. Fenitrothion was more potent as an inhibitor than the three S-n-propyl derivatives. Incubation of hepatic protein enhanced ChE inhibition in brain in the case of fenitrothion, while it reduced the inhibitory effect of the S-n-propyl derivatives. On the other hand, the four organophosphorus esters caused hypoglycemia in both male and female rats and also reduced their blood urea with different degrees.