Alterations in phospholipid biosynthesis by polychlorinated biphenyls and polychlorinated biphenylols.

Inhibition and stimulation of synthesis of phospholipids by polychlorinated biphenyls (PCB) have been reported by several authors. The mode of action of PCB on the synthesis of phospholipids has not been determined. Results of experiments in the present report indicate that both PCB and polychlorinated biphenylols alter the activities of key enzymes of glyceride and phospholipid synthesis. 4-Chloro-4-biphenylol (CB-OH), 2',3',4',5,5'-pentachlorobiphenylol (PCB-OH) and 2,4,5,2',4',5'-hexachlorobiphenyl (HCB) inhibited sn-glycerol-3-phosphate acyltransferase activity. Inhibition by PCB-OH was noncompetitive with apparent Ki of 2.6 X 10(-4) M. PCB-OH stimulated phosphatidase activity, but no apparent change was observed with CB-OH. PCB inhibited phosphorylcholine glyceride transferase activity, but had no significant effect on diglyceride acyl transferase.

Assessing the Effect of Composting Cassava Peel Based Substrates on the Yield, Nutritional Quality, and Physical Characteristics of Pleurotus ostreatus (Jacq. ex Fr.) Kummer.

Cassava peel based substrate formulations as an alternative substrate were used to grow mushrooms. The effect of two compost heights, three composting periods on the mycelia growth, physical characteristics, yield, and nutritional qualities of Pleurotus ostreatus (Jacq. ex Fr.) Kummer was studied. Mean mycelia growth of 16.2 cm after a period of seven (7) weeks was the best for 1.5 m compost height. Cap diameter and stipe length differed significantly (P < 0.05) with the compost heights (0.8 m and 1.5 m). The yield on compost height of 1.5 m, composted for 5 days, differed significantly (P < 0.05) from that of 0.8 m and gave increasing yields as follows: cassava peels and manure, cassava peels only, cassava peels and corn cobs (1 : 1 ratio), and cassava peels and corn cobs (1 : 1 ratio) with chicken manure. Composting periods (3 and 7 days) gave varying yields depending on the compost height. Based on the findings an interaction of 1.5 m compost height and 5 days composting period on cassava peels and corncobs (1 : 1 ratio) with chicken manure produced the best results. The nutritional quality of the mushrooms also differed significantly (P < 0.05), indicating that cassava peels could be used as a possible substrate in cultivation of mushroom.

The incidence of malaria and the comparison of hematological and biochemical indices of Plasmodium falciparum-parasitemic and aparasitemic sickle cell disease (SCD) patients.

Hemolytic anemia is common in sickle cell disease (SCD), but the course and extent differ, depending on genetic, epigenetic, and environmental factors. In the malaria-endemic tropical environment, some vulnerable subjects would be infected and the impact of infection would vary. Therefore, this study was to find malaria incidence and the associated changes in some laboratory indices in 330 SCD subjects. Following blood smear preparation for falciparum detection, hematological and biochemical indices were measured for a comparison of parasitemic and age-matched, genotype-matched, and sex-matched nonparasitemics. For sixty-nine parasitemics, constituting about 21% of all subjects studied, and sixty-six matched nonparasitemics, hematological indices (hemoglobin, white-cell count, red-cell count, mean cellular volume, reticulocyte count, and HbF) as well as biochemical indices (LDH, total bilirubin, AST, and ALT) were determined. For all quantities, except the reticulocyte count (12.3% ± 12.4% for parasitemics and 23.6% ± 17.7% for nonparasitemics), no statistically significant differences were observed. Classification of both cohorts according to their genotypes showed some intergenotypic differences for hemoglobin and WBC counts. Mathematical modeling of the reticulocyte counts shows the distribution in the parasitemics followed an exponential pattern, while the nonparasitemic showed a polynomial distribution, with each model characterized by an equation of best fit. The study has shown about 21% incidence of parasitemia. All differences in the indices can be seen as normal variations, unattributable to the malaria infection. However, the lower reticulocyte count in the parasitemic is a reflection of lowered erythropoietic activity because of the infection.

Polychlorinated biphenyls: in vivo and in vitro modifications of phospholipid and glyceride biosynthesis.

In vivo administration of Aroclor 1254 (PCB) alters the biosynthesis of glycerides and phospholipids. Different percentages of total radioactivity distribution patterns were observed in microsome, mitochondria, and homogenate preparations from rat liver. (14C)palmitate and (U-14C)sn-glycerol-3-phosphate were differently incorporated when assayed in the same preparation, suggesting compartmentation of the substrates. Acyl CoA sn-glycerol-3-phosphate acyl transferase was inhibited by PCB in vitro. Inhibition was noncompetitive. After 30 days of dietary pretreatment with PCB, acyl CoA sn-glycerol-3-phosphate acyl transferase activity was increased in the liver. In vitro, the total radioactivity incorporated into phospholipids and glycerides was decreased in the presence of PCB. There was, however, no significant change in the percent of total distribution of radioactivity when either (U-14C)sn-glycerol-3-phosphate or (1-14C)palmitate was the substrate. PCB had no significant effect on glycerol kinase activity. PCB initially did not inhibit phosphatidate, but after prolonged incubation there was a small increase or decrease under in vitro and in vivo conditions respectively. Phosphorylase b, but not phosphorylase a, was inhibited by PCB. 2,4,5,2'4',5'-hexachlorobiphenyl inhibited sn-glycerol-3-phosphate acyl transferase, phospholipid biosynthesis, and glyceride biosynthesis. The results indicate that PCB alters biosynthesis of phospholipids and glycerides in vitro and in vivo. Apparent differences between the results obtained under the two conditions are probably due to qualitative and/or quantitative variations in metabolic products formed from PCB in vivo.