Effect of Ocimum gratissimum Leaf-extract on Hematological Indices and Lipid Profile of Streptozotocin-induced Diabetic Wistar Rats.

BACKGROUND AND OBJECTIVE: Ocimum gratissimum (OG) has been used in ethnopharmacology for the treatment of diabetes. The aim of the study was to evaluate the effect of Ocimum gratissimum leaf-extract on hematological indices and lipid profile of Streptozotocin-induced diabetic Wistar rats. MATERIALS AND METHODS: Twenty-four rats weighing 100-160 g were randomly assigned to four treatment groups, the normal and diabetic controls, received a placebo treatment, while groups three and four were administered glibenclamide and OG leaf-extract (400 mg kg-1 b.wt.), respectively. The extracts were administered twice daily for 28 days. The rats were sacrificed and whole blood was collected for hematological and serum lipid profile assays. Data were analyzed using one-way ANOVA. RESULTS: Diabetes induction resulted in decreases (p<0.05) in Red Blood Cell (RBC), Hemoglobin (Hb), White Blood Cell (WBC) and increases in Mean Corpuscular Hemoglobin and Blood platelets compared to the normal control. Treatment with O. gratissimum extract reversed RBC (7.74±0.39 µL), WBC (16.57±3.02) and Platelet (804.33±194.02) levels, but not Hb, towards normal levels (7.99±0.04, 11.27±0.69, 839.67±10.17 respectively). Diabetes induction also resulted in increases (p<0.05) in Triglyceride (TG) and Very-Low-Density Lipoprotein (VLDL), decreases (p<0.05) in High-Density Lipoprotein (HDL) and Low-Density Lipoprotein (LDL) compared to normal control with no significant change in Total Cholesterol (TC). After administration with Ocimum gratissimum TC, LDL and VLDL and HDL levels were significantly (p<0.05) reduced relative to the diabetic control. TG was however increased relative to the diabetic control. CONCLUSION: Overall, data suggests the plant holds great potential in amelioration of diabetes-induced dyslipidemia and hematological disorders.

Crystallization and preliminary X-ray investigation of Escherichia coli porphobilinogen deaminase.

Porphobilinogen deaminase, the polymerase that catalyses the synthesis of preuroporphyrinogen, the linear tetrapyrrole precursor of uroporphyrinogen III, has been crystallized from sodium acetate buffer with polyethylene glycol 6000 as precipitant. The crystals are orthorhombic and the space group is P2(1)2(1)2, with unit cell dimensions a = 88.01 A, b = 75.86 A, c = 50.53 A and alpha = beta = gamma = 90 degrees, indicating a single molecule of 34 kDa in the asymmetric unit. The crystals grow to dimensions of 1 mm x 2 mm x 0.5 mm within two weeks in the dark and are stable in the X-ray beam for at least 40 hours. Diffraction data beyond 1.7 A resolution, observed with a synchrotron radiation source, indicate that a high resolution structure analysis is feasible.

Purification and properties of uroporphyrinogen III synthase (co-synthase) from an overproducing recombinant strain of Escherichia coli K-12.

The Escherichia coli hemD gene, encoding the enzyme uroporphyrinogen III synthase (co-synthase), was cloned into multi-copy plasmids in E. coli cells that were used to generate strains producing up to 1000 times the concentration of the synthase in the wild-type. The enzyme was purified to homogeneity from these strains in milligram amounts. The enzyme is a monomer of Mr 28,000 with an isoelectric point of 5.2 and a pH optimum of 7.8. The specific activity of the purified synthase is 1500 units/mg and the Km for the substrate, pre-uroporphyrinogen, is 5 microM. The N-terminal sequence of the enzyme is Ser-Ile-Leu-Val-Thr-Arg-Pro-Ser-Pro-Ala-Gly-, in agreement with the gene-derived protein sequence. The enzyme contains four 5,5'-dithiobis-(2-nitrobenzoic acid)-titratable groups, one reacting rapidly with the reagent and three further groups having lower reactivity. The enzyme is heat-sensitive, and during heat inactivation all four thiol groups become equally available for reaction.

Nucleotide sequence for the hemD gene of Escherichia coli encoding uroporphyrinogen III synthase and initial evidence for a hem operon.

1. The hemD gene, encoding uroporphyrinogen III synthase, has been located adjacent to the hemC gene at 85 min on the Escherichia coli chromosome. 2. The entire nucleotide sequence (741 base pairs) of the hemD gene is reported. 3. E. coli strains harbouring plasmics containing the hemD gene produce greatly elevated levels of uroporphyrinogen III synthase. 4. Purified uroporphyrinogen III synthase, isolated from the hemD-containing strain ST1046, has an Mr of 29,000, in close agreement with that predicted from the nucleotide sequence. 5. The existence of a hem operon is suggested.