Oral administration of orthovanadate and Trigonella foenum graecum seed powder restore the activities of mitochondrial enzymes in tissues of alloxan-induced diabetic rats

The effect of oral administration of sodium orthovanadate (SOV) and Trigonella foenum graecum seed powder (TSP), a medicinal plant used extensively in Asia, on the mitochondrial metabolism in the alloxan diabetic rats has been investigated. Rats were injected with alloxan monohydrate (20 mg/100 g body wt) or vehicle (Na-acetate buffer), the former were treated with either 2 IU insulin i.p., 0.6 mg/ml SOV ad libitum, 5% TSP ad libitum, and a combination of 0.2% SOV and 5% TSP ad libitum for 21 days. Selected rate-limiting enzymes of the tricarboxylic acid cycle, hydrogen shuttle system, ketone body metabolism, amino acid metabolism and urea cycle were measured in the mitochondrial and cytosolic fractions of liver, kidney and brain tissues of the experimental rats. Majority of the mitochondrial enzymes in the tissues of the diabetic rats had significantly higher activities compared to the control rats. Similarly, the activities of mitochondrial and cytosolic aminotransferases and arginase were significantly higher in liver and kidney tissues of the diabetic rats. The separate administrations of SOV and TSP to diabetic rats were able to restore the activities of these enzymes to control values. The lower dose of SOV (0.2%) administered in combination with TSP to diabetic rats lowered the enzyme activities more significantly than when given in a higher dose (0.6%) separately. This is the first report of the effective combined action of oral SOV and TSP in ameliorating the altered mitochondrial enzyme activities during experimental type-1 diabetes. Our novel combined oral administration of SOV and TSP to diabetic rats thus conclusively proves as a possible method to minimize potential vanadate toxicity without compromising its positive effects in the therapy of experimental type-1 diabetes.     

A <Emphasis Type="Italic">Bacillus thuringiensis</Emphasis> Isolate Possessing a Spore-Associated Filament

We report on a novel bacterium, isolated during a screen for environmental isolates of Bacillus thuringiensis, that possesses a novel filamentous structure. Nucleotide sequence from the isolates 16S rRNA gene places the bacterium unambiguously within the Bacillus thuringiensis/Bacillus cereus group. Phase-contrast and electron microscopy indicate the presence of both a parasporal body and a long filament which are retained after sporulation. The filament is shown to consistently arise from the end of the exosporium and next to the parasporal body. Upon spore germination, the parasporal body/filament complex is retained on the cell wall of the resulting bacterium.Received: 4 March 2003 / Accepted: 18 April 2003     

A Bacillus thuringiensis isolate possessing a spore-associated filament

We report on a novel bacterium, isolated during a screen for environmental isolates of Bacillus thuringiensis, that possesses a novel filamentous structure. Nucleotide sequence from the isolate's 16S rRNA gene places the bacterium unambiguously within the Bacillus thuringiensis/Bacillus cereus group. Phase-contrast and electron microscopy indicate the presence of both a parasporal body and a long filament which are retained after sporulation. The filament is shown to consistently arise from the end of the exosporium and next to the parasporal body. Upon spore germination, the parasporal body/filament complex is retained on the cell wall of the resulting bacterium.     

Solubilization of benzodiazepine binding site from rat cortex.

The high-affinity binding site for [³H] diazepam has been solubilized from rat brain using 0.5% Lubrol-PX. Using a polyethylene glycol (PEG)-γ-globulin assay, it has been possible to demonstrate solubilization of about 60% of the binding sites in a single step. The solubilized binding site possesses a K_D of 11 nM for [³H] diazepam compared to approximately 4 nM for the membrane-bound form, and binding is to a single class of sites. The order of potency of benzodiazepines is identical for the solubilized receptor and the membrane-bound form. Binding of [³H] diazepam is temperature dependent and higher at 4° than 37°C. Both urea and guanidine-HC1 were capable of totally inhibiting binding, and this inhibition was partly reversible; neither sulfhydryl groups nor carbohydrate moieties seem to be important for binding. γ-Aminobutyric acid which enhanced [³H] diazepam binding to membrane fractions was without effect on the solubilized binding site.     

Preliminary structural studies of the hydrophobic ribosomal P0 protein from Trypanosoma cruzi, a part of the P0/P1/P2 complex

The Trypanosoma cruzi ribosomal P0 protein (TcP0) is part of the ribosomal stalk, which is an elongated lateral protuberance of the large ribosomal subunit involved in the translocation step of protein synthesis. The TcP0 C-terminal peptide is highly antigenic and a major target of the antibody response in patients with systemic lupus erythematosus and patients suffering chronic heart disease produced by Trypanosoma cruzi infection. The structural properties of TcP0 have been explored by circular dichroism, tryptophan fluorescence and limited proteolysis experiments. These studies were complemented by secondary structure consensus prediction analysis. The results suggest that the tertiary structure of TcP0 could be described as a compact, stable, trypsin-resistant, 200 residues long N-terminal domain belonging to the alpha/beta class and a more flexible, degradable, helical, 123 residues long C-terminal domain which could be involved in the formation of an unusual hydrophobic zipper with the ribosomal P1/P2 proteins to form the P0/P1/P2 complex.     

Association between the angiotensin-converting enzyme gene insertion/deletion polymorphism and essential hypertension in young Pakistani patients

Several studies have demonstrated the importance of angiotensin-converting enzyme (ACE) insertion (I)/deletion (D) polymorphisms in the pathogenesis of hypertension. This study sought to determine the association between the ACE I/D polymorphism and essential hypertension in young Pakistanis. The frequency of the ACE I/D polymorphism was established by a comparative cross-sectional survey of Pakistani patients suffering from essential hypertension and ethnically matched normotensive controls. Samples were collected from tertiary care hospitals in northern Pakistan. Hypertensive individuals were defined as those with a systolic blood pressure > 140 mmHg and/or diastolic blood pressure > 90 mmHg on three separate occasions, or those currently receiving one, or more, anti-hypertensive agents. DNA samples obtained from hypertensive (n = 211) and normotensive (n = 108) individuals were typed by PCR. The frequency of the ACE I/I genotype was significantly higher in hypertensive patients, aged 20-40 years, than in normotensive controls of the same age group (chi(2) = 4.0, P = 0.041). Whereas no overall significant differences were observed between the I/I, I/D and D/D ACE genotypes (One way ANOVA, F = 0.672; P = 0.413). The association between the ACE I/I genotype and essential hypertension in individuals aged 相似文献   

Physiological aspects of hydrocarbon emulsification, metal resistance and DNA profile of biodegrading bacteria isolated from oil polluted sites

The production of biosurfactants was evaluated for seven bacterial strains isolated from different oil contaminated sites by the Emulsification Index using diesel oil as the hydrocarbon source. Minimum Inhibitory Concentrations of Mg²⁺, Cr³⁺ and Cu²⁺ were determined to identify the less sensitive bacteria in order to select the best strains for bioremediation. Plasmid extraction was also performed in order to search for gene sequences involved with biosurfactant synthesis. All strains were able to emulsify diesel oil. Rhodococcus ruber AC239 presented the best index (58%), followed by other Rhodococcus strains. Pseudomonas aeruginosa, R. ruber AC239, AC87 and R. erytropolis AC272 presented smallest sensitivities to heavy metals used, being suitable for use in sites contaminated with high concentrations of them. No plasmid DNA was detected showing that biosurfactant coding genes should be in the chromosomal DNA.     

Expression kinetics and plasmid stability of recombinant E. coli encoding urease-derived peptide with bioinsecticide activity

The nucleotide sequence encoding for an insecticidal peptide derived from the Canavalia ensiformis urease gene jbureII (AF 468788), was cloned and expressed in the pET101/Escherichia coli expression system. Bacterial cultivation in shaker with lactose as inducer produced 1.26 μg of recombinant peptide/mg protein, after 8 h of growth. The plasmid stability and the expression of the recombinant peptide were studied in bioreactor. Expression of the recombinant peptide was strongly affected by pH of cultures, with a decrease of more than 50% when acidification was freely allowed. Likewise, peptide production and plasmid stability were shown to be affected by aeration and agitation speed, both decreasing for higher values of oxygen mass transfer rates. Despite these difficulties, in bioreactor cultures carried out with controlled pH, low oxygen mass transfer rates and using lactose as inducer, we were able to achieve a total peptide production of 7.14 μg/mg protein, which represents approximately 2% of total cell protein. Bioassays were carried out using the purified peptide on insect models. The peptide fed to Dysdercus peruvianus nymphs produced 100% mortality after 11 days, deaths starting with a lag phase of 3–4 days, confirming that the bioreactor-produced peptide retained its biological activity.