The alterations and abnormalities in hormone-sensitive adenylyl cyclase (AC) system occur at early stages of the type 2 diabetes mellitus (T2DM) and at later stages of the disease they are, according to our view, one of the factors causing T2DM complications. To study the changes in AC system likely to be involved in the development of these complications one needs a very long model of T2DM.
Purpose: The aim of this work was the study of AC system in the myocardium, brain and testes of three-, eight- and 18-month-old male rats with experimental T2DM compared with control animals of the same age.
Methodology: Neonatal model of T2DM was induced by the treatment of five-day pups with streptozotocin (80 mg/kg), at the age of three months streptozotocin-treated rats had glucose tolerance. The determination of the basal AC activity and its regulation by hormones was carried out in the plasma membranes from the tissues of diabetic and control rats, using [a-32P]-ATP as substrate.
Results: With increasing age, three to 18 months, in the myocardium and testes of diabetic and control rats the AC stimulating effects of b-agonists and relaxin (myocardium), and gonadotropin and PACAP-38 (testes) decreased, in diabetic rats to a much greater extent. In the brain the influence of age on AC stimulation by hormones was less pronounced, and only AC effect of PACAP-38 drastically decreased in 18-month-old diabetic and control rats. AC inhibitory effects of somatostatin (all investigated tissues), 5-nonyloxytryptamine (brain) and noradrenaline (myocardium) reduced in eight- and 18-month-old diabetic rats, indicating the weakening of AC inhibiting pathways in a rat model of T2DM.
Conclusion: The hormonal regulation of AC system in the brain, myocardium and testes of 18-month-old control and diabetic rats significantly weakened, and in very long T2DM these abnormalities induced by the combined influence of DM and aging are expressed to a large extent.
Aim: This research work was designed to determine the effect of germination on catalytic capacity of urease extracted from seven beans samples.
Study Design: Experimental.
PlaceandDuration: Department of Biochemistry, School of Science and Science Education, Federal University of Technology, Minna, Nigeria, between December, 2010 and September, 2011.
Methodology: Seven samples of beans namely; Phaseolus lunatus, Parchyrhizus tuberrosus, Glycine max, Cajanus cajan, Mucuna pruriens, Kerstings geocarpa and Vigna mungo were used by comparing urease activity in germinated to ungerminated beans samples.
Result: The protein level in germinated and ungerminated beans samples as well as, optimum pH, optimum temperature, substrate concentration and kinetic parameters, Vmax, Km, and Vmax/Km of urease were determined. The pH, temperature and substrate concentration ranged from 5.50-8.0, 30-80ºC and 0.1-0.6M respectively. From the results, the protein level in germinated beans samples reduced significantly (p<0.05) compared to ungerminated beans samples. The optimum pH and temperature ranged from 6.5-7.0 and 60-70ºC respectively for both germinated and ungerminated beans sample. Therefore, germination did not affect the pH and temperature stability of urease when compared to ungerminated beans samples. The results showed that germination significantly (p=0.05) increased Vmaxand there was no significant (p=0.05) difference in Km of urease in germinated and ungerminated beans sample studied. However, the catalytic capacity (Vmax/Km) of urease in germinated beans was significantly (p=0.05) higher than ungerminated.
Conclusion: This implies that, with germination urease activity can be increased to meet both application of urea as fertilizer (agriculture), clinical analysis of urea in biological fluid, artificial kidney development and other applications.
Surface-layers (S-layers) are macromolecular paracrystalline arrays of proteins or glycoproteins that can self-assemble into 2-dimensional semi-permeable meshworks to overlay the cell surface of many bacteria and archaea. They usually assemble into lattices with oblique, square or hexagonal symmetry and serve as an interface between the bacterial cell and the environment. Isolated S-layers can recrystallize into two-dimensional regular arrays in suspension or on various surfaces, thus being an appropriate material for several bionanotechnological purposes. Promising applications of S-layers include their use as biotemplates for the capture of metal ions or the synthesis of metal nanoclusters. Considering the use of S-layers as biotemplates for the organization of metal ions or metallic nanoclusters, research on potential of surface layer proteins (SLP) and metals can be understood as an interdisciplinary field, in which different biophysical techniques supply complementary information. In this review, we discuss the SLP as native or engineered “bottom-up” building blocks for metal immobilization structures. We also describe the biophysical techniques used to analyze metal binding properties as well as the information obtained from the investigation of these structures.
Among the HIV / AIDS infected, individuals contract fungal infections of which many die as a direct consequence of these infections. In this study, the antifungal activity of ten extracts (stem bark) from Terminalia mantaly H. Perrier was evaluated on the in vitro growth of clinical isolate of pathogenic fungi (Cryptococcus neoformans). Agar double dilution method in slope tubes was adopted to determine anticryptococcal activity. All extracts exhibited antifungal activity in dose-response relationship. The residue extracts T4-2 obtained after degreasing the hydro-alcoholic extract T0 (MFC = 24.37μg/Ml; IC50 = 5.87μg/mL) is the most active extract. Moreover, for a given concentration it is said that there are not significant differences between the different tests for each extract (P< 0.05). Therefore, using the hydro-alcoholic solvent (70% ethanol) followed by removal of oil is the best way to obtain an optimally concentrated active ingredient from Terminalia mantaly. The present study justifies the traditional use of this plant for the treatment of fungal infections.
The interaction between tubular epithelial cells and calcium oxalate crystals or oxalate ions is a very precarious event in the lithogenesis. Urine contains ions, glycoproteins and glycosaminoglycans that inhibit the crystallization process and may protect the kidney against lithogenesis.
Hundred patients (24 women and 76 men) with a history of stone disease and hundred controls (25 women and 75 men) were evaluated for urinary GAG concentration. By using a new dye-binding assay, the total GAG concentration in the urine was measured and corrected to urinary creatinine levels (milligram of GAG per gram creatinine).
There was a preponderance of urinary stones in males; the highest incidence being in Group 2. Excretion of GAGs in 24-hour urine sample was significantly lower in patients compared to controls, for males in all age groups and for females, however, there was no statistically significant difference in the urinary GAGs value between males and females in a given age group for either controls or patients. The urinary GAGs excretion idecreased with age in controls, but the levels in patients were lower.
Conclusion: This study shows that low urinary GAGs are associated with urinary stones in patients. Our study lead us to propose that urinary GAG may play an important role in the prevention and reduction of calculi in patients with urolithiasis. Lower urinary GAG levels are more common in patients with stone formation. This may play a more determinant role in male patients and those with recurrent stone formation. We conclude that uric acid can constitute an important risk factor for calcium oxalate urolithiasis through heterogeneous nucleation and the GAGs can play an important role as preventive agents.