Biocrystallization of silver and gold ions by inactive cell filtrate of Rhizopus stolonifer.

Microbes and their cell filtrates are known to synthesize metal nanoparticles. But maintenance of aseptic conditions and irregularly shaped and sized nanoparticles are major drawbacks of the system. In this study cell filtrate from inactive biomass of Rhizopus stolonifer was used for the first time to produce near uniformly sized and shaped Ag and Au nanoparticles at room temperature. The size of Ag and Au nanoparticles were found in the range of 25-30 nm and 1-5 nm, respectively. UV-vis spectrum, TEM and XRD measurements confirmed the formation of Ag and Au nanoparticles.

Bioreduction of trivalent aurum to nano-crystalline gold particles by active and inactive cells and cell-free extract of Aspergillus oryzae var. viridis.

Bioreduction efficacy of both active (AB) and inactive (IB) cells/biomass of Aspergillus oryzae var. viridis and their respective cell-free extracts (ACE and ICE) to convert trivalent aurum to gold nanoparticles were tested in the present study. Strong plasmon resonance of gold nanoparticles was observed between 540 and 560 nm in the samples obtained from AB, IB, ACE and ICE. Transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray (EDX) and X-ray diffraction (XRD) were performed to examine the formation of gold nanoparticles. Comparing all four forms of A. oryzae var. viridis, ICE showed high gold nanoparticle productivity. The nanoparticles formed were quite uniform in shape and ranged in size from 10 to 60 nm. In addition some triangle, pentagon and hexagon-shaped nanoplates with size range of 30-400 nm were also synthesized especially at lower pH. Organics from the inactive cells are believed to be responsible for reduction of trivalent aurum to nano-sized gold particles. Organic content of the ICE was found to be double the amount of ACE. High productivity of gold nanoparticles by metabolic-independent process opens up an interesting area of nanoparticle synthesis using waste fungal biomass from industries.

Effect of Lactobacillus gasseri BNR17 on blood glucose levels and body weight in a mouse model of type 2 diabetes.

AIMS: To investigate the effect of Lactobacillus gasseri BNR17 isolated from human breast milk on blood glucose and body weight in type 2 diabetic animals. METHODS AND RESULTS: db/db mice were divided into one control group and five sample groups; the sample groups received BNR17 (10(7), 10(8), 10(9) and 10(10) CFU) or rosiglitazone (8 mg kg(-1)) orally twice a day for 12 weeks. BNR17 groups had a dose-dependent reduction in food, water intake and amount of excrement. Body weight loss was not seen in the BNR17 groups. Fasting and postprandial 2 h blood glucose levels were significantly lower in the BNR17 (10(10) CFU) group compared with the control group. HbA1c decreased in the BNR17 group, although it was not statistically significant. During the oral glucose tolerance test, the BNR17 groups exhibited dose-dependent improvement in glucose sensitivity. CONCLUSIONS: Lactobacillus gasseri BNR17 has a suppressing effect on blood glucose levels and improved diabetic symptoms in db/db mice. SIGNIFICANCE AND IMPACT OF THE STUDY: Blood glucose-lowering lactic acid bacteria are expected to be useful as a therapeutic for treating type 2 diabetes in humans.

Prebiopsy localisation of impalpable breast lesions.

Prebiopsy localization of impalpable breast lesions (IBL) assures removal of suspicious mammographically detected lesions. Specimen radiograph of the excised specimen is mandatory to confirm complete excision. The aim of this study was to audit our series of percutaneous hookwire localization and to determine the positive biopsy rate of the mammographically detected impalpable breast lesion in our center. Thirty-eight patients with suspicious IBL underwent excision biopsy under mammographic localization in our unit from late February 1998 to May 2003. The excised specimen is immobilized and compressed within the Transpec device. This device incorporates a reference grid visible in the specimen radiograph. Hence, the target lesion marked in the reference grid of the specimen radiograph will allow precise examination and exact localization of the suspicious lesion by the pathologist. The positive biopsy rate for malignant lesion was 26.3%, the majority fall in the range of 40-59 age group. Thirty-two (84.2%) of the patients had clustered micro-calcifications, 4 (10.5%) had impalpable mass lesions and in 2 (5.3%) spiculated lesions were seen on the preoperative mammogram. Mammographic feature of clustered micro-calcification accounts for all the malignant lesions in our series. Utilization of Transpec device has shown to be practical, reliable and cost effective in the management of IBL. Nonetheless, it should be emphasized that optimal specimen radiography and pathological correlation requires close cooperation between radiologist, surgeon and pathologist.

Purification and some properties of a beta-glucosidase from Trichoderma harzianum type C-4.

Type C-4 strain of Trichoderma harzianum was isolated as a microorganism with high cellulolytic activity. Beta-glucosidase is involved in the last step of cellulose saccharification by degrading cellobiose to glucose, and plays an important role in the cellulase enzyme system with a synergic action with endoglucanase and cellobiohydrolase for cellulose degradation. Beta-glucosidase from T. harzianum type C-4 was purified to homogeneity through Sephacryl S-300, DEAE-Sephadex A-50, and Mono P column chromatographies. It was a single polypeptide with the molecular mass of 75,000 by SDS-PAGE. The enzyme was very active at pH 5.0 and 45 degrees C. No significant inhibition was observed in the presence of metal ions, thiol reagents, or EDTA. The enzyme was stable in the presence of 5% ox gall and digestive enzymes. p-Nitrophenyl-beta-D-cellobioside worked as a substrate for the enzyme as much as p-nitrophenyl-beta-glucopyranoside. Glucose and gluconolactone showed competitive inhibition with a Ki of 1 mM and 1.8 microM, respectively, while galactose, mannose, and xylose did not inhibit the enzyme significantly.

Peptidases affecting recombinant protein production by Streptomyces lividans.

The influence of peptidases on human interleukin-3 (rhIL-3) production by a recombinant Streptomyces lividans strain was investigated. The bacterium produced several general peptidases and tripeptidyl peptidases compromising the authenticity of rhIL-3. The level of peptidases depended on growth morphology. Growing S. lividans as compact pellets successfully reduced peptidase activity. Maximum general peptidase activity in pellet culture was delayed after maximum rhIL-3 concentration was achieved. The activity of the tripeptidyl peptidase was product (rhIL-3) associated.

Characterization of angiotensin II antagonism displayed by SK-1080, a novel nonpeptide AT1-receptor antagonist.

The pharmacologic profile of SK-1080, a nonpeptide AT1-selective angiotensin-receptor antagonist, was investigated by receptor-binding studies, functional in vitro assays with rabbit and rat aorta, and in vivo experiments in pithed rats. SK-1080 inhibited the specific binding of [125I]-[Sar1, Ile8]-angiotensin II to human recombinant AT1 receptor with a 12-fold greater potency than losartan [median inhibitory concentration (IC50): 1.01 and 12.3 nM, respectively], but it did not inhibit the binding of [125I]-CGP 42112A to human recombinant AT2 receptor (IC50: >10 microM for both). The Hill coefficient for the competition curve of SK-1080 against AT1 receptor was not significantly different from unity (0.96). Scatchard analysis showed that SK-1080 interacted with human recombinant AT1 receptor in a competitive manner, as with losartan. In functional studies with rat and rabbit aorta, SK-1080 competitively inhibited the contractile response to angiotensin II (pKB values: 9.97 and 9.51, respectively) with 15-25% decrease in the maximal contractile responses, unlike losartan, which showed competitive antagonism without any change in the maximal contractile responses to angiotensin II (pA2 values, 8.02 and 7.59, respectively). In pithed rats, SK-1080 (i.v.) induced a nonparallel right shift in the dose-pressor response curve to angiotensin II (ID50, 0.07 mg/kg) with a dose-dependent reduction in the maximal responses; this antagonistic effect was approximately 25 times more potent than losartan (ID50, 1.74 mg/kg), which showed competitive antagonism. SK-1080 did not alter the responses induced by other agonists such as norepinephrine, KCI, and vasopressin in isolated rabbit aorta and pithed rats. These results suggest that SK-1080 is a highly potent AT1-selective angiotensin II-receptor antagonist with a mode of insurmountable antagonism.