2,110 research outputs found
Effect of Various Nutritional Supplements on Hyaluronic Acid Production
Effect of various nutritional supplementations on production of hyaluronic acid (HA) using Streptococcus equi subsp. zooepidemicus ATCC 39920 was evaluated at shake flask. Among the different carbon sources used, maltodextin showed HA of 0.9 g/L followed by 0.7 g/L for dextrose. L-arginine HCl at 2.0 g/L increased the yield of HA from 0.7 g/L to 0.85 g/L. L-arginine and L-glutamine showed the yield of HA of 0.7 g/L and 1.0 g/L, respectively at 2.0 g/L concentration. L-glutamine (2.0 g/L) and uridine (0.75 g/L) showed HA yield of 0.8 and 1.045 g/L, respectively. Addition of sodium glucuronate at 0.25 g/L concentration at 8 h, the yield of HA was increased from 0.7 g/L to 0.85 g/L. Pantothenic acid at concentration of 8.33 mg/L supplemented to the P10 medium, yield of 0.87 g/L of HA was obtained. Active dry yeast at 5.0 g/L increased yield of HA from 0.7 g/L to 0.85 g/L. Tween 80 at higher concentration reduced HA production. The addition of MgSO4.7H2O at 1.0 g/L improved the production of HA. Other metal ions like manganese, ferrous, copper, and zinc have no significant effect on HA production. Thus, it has been found that various nutritional supplements have effect on production of HA using S. equi subsp. zooepidemicus ATCC 39920
Effect of Various Physical Parameters and Statistical Medium Optimization on Production of Hyaluronic Acid Using S. Equi Subsp. Zooepidemicus ATCC 39920
It has been shown that initial conditions for bacterial cultivation are extremely important for the successful production of hyaluronic acid (HA) by fermentation. We investigated several physical parameters that affect productivity of HA under shake flask. i.e. transfer criteria of seed, agitation and aeration of fermentation flasks. Among the various physical parameters studied, inoculum age of 8-10 h, pH 6.4, optical density (600 nm) 2.0 and 3% level inoculum transfer found to be optimum. After inoculating with Streptococcus equi subsp. zooepidemicus ATCC 39920, the temperature 37 0C and 90 rpm found optimum during growth as well as for the HA production. The fractional factorial design of six factors with two levels showed yeast extract, potassium dihydrogen phosphate and sodium bicarbonate as significant model terms. The factor potassium dihydrogen phosphate was relatively more significant than yeast extract.
ANTIFUNGAL ACTIVITY OF LIPASE MODIFIED FLAVONOIDS FROM CITRUS LIMETTA
Objective: The aim of the present study is to bring about enzymatic modification of flavonoids from Citrus limetta in order to increase their antifungal activity.
Methods: Methanolic extraction of flavonoids from citrus peels was carried out and their presence was confirmed by various tests. Crude extract of flavonoids was subjected to enzymatic modification by enzyme lipase in presence of acyl donor tributyrin in order to bring about esterification. Esterification was confirmed using IR spectroscopy and sodium hydroxide- phenolphthalein test. Antifungal activity of the treated sample and control sample were tested against Candida albicans and compared with fluconazole by Kirby Bauer disk diffusion method.
Results: Methanolic extract showed the presence of flavonoids on carrying out various test. While testing enzymatic modification, IR spectra did not show a significant difference between treated and control; however, enhanced esterification was confirmed by sodium hydroxide-phenolphthalein test. On carrying out antifungal activity, treated samples showed a 56.52% increase in zone of inhibition against Canidida albicans as compared to the control and was also found to be more in comparison to fluconazole.
Conclusion: The results signify that enzymatic modification increases the antifungal activity of flavonoids from Citrus limetta
COLISTIN-CARBAPENEM COMBINATION THERAPY AGAINST CARBAPENEM RESISTANT GRAM NEGATIVE BACILLI INFECTIONS: CLINICAL AND AN IN VITRO SYNERGY STUDY
Objective: Combination therapy is recommended for carbapenem resistant Gram negative bacilli (CR GNB) infections. However, limited data exists on the clinical effectiveness of antibiotic combinations. The purpose of this study was to evaluate the efficacy of colistin-carbapenem combination against CR GNB infection in a clinical study and an in vitro synergy study using Etest.
Methods: A study was conducted in a tertiary care hospital to evaluate the clinical outcome of patients with CR GNB infections who were treated with colistin-carbapenemcombination between January to April, 2013. It was comprised of 33 patients with CR GNB infection. Detection of in vitro synergy was performed by Etest for colistin-meropenem combination on five isolates. These isolates were also screened for the resistant genes blaOXA-23, blaVIMand blaNDM using single target PCR.
Results: 33 CR GNB included Acinetobacterspp. (19), Pseudomonas aeruginosa (7) and Enterobacteriaceae spp. (7). Overall clinical success of 60.6% was observed in patients receiving colistin-carbapenem combination therapy. In respiratory infection, the clinical success rate was only 25%, whereas in soft tissue infection it was 57.1%. In bloodstream infection 100% Â clinical success was observed. All five isolates screened using PCR was carrying bla NDM gene, whereas isolate of Acinetobacter baumannii also carried blaOXA-23 and blaVIM gene. Indifferent interactions were observed between colistin and meropenem against all five isolates.
Conclusion: We observed low clinical success rate for colistin-carbapenem combination therapy, probably due to indifferent interactions between colistin and meropenem against NDM producing strain. In addition, probable pharmacokinetic concern of colistin may have a role to play
CHARACTERIZATION OF CARBAPENEM RESISTANT ACINETOBACTER BAUMANNII ISOLATED IN A TERTIARY CARE HOSPITAL: EPIDEMIOLOGY AND TREATMENT OUTCOME
Objective: Carbapenem resistant Acinetobacter baumannii (CR-Ab) has emerged as a major nosocomial pathogen, but optimal treatment regimens are unknown. Our objectives were to determine the epidemiology and outcome of CR-Ab infections at a tertiary care hospital.Methods: CR-Ab isolates were collected from January to April 2013. MICs were determined and isolates were subjected to screening for carbapenemase production by Modified Hodge test (MHT), metallo-β-lactamase (MBLs) by EDTA disk synergy test and AmpC β-lactamase by AmpC disk test. 15 isolates were subjected to PCR for detection of resistant genes, blaOXA-23, blaVIM and blaNDM. Treatment outcomes of infections were evaluated.Results: 51 CR-Ab isolates from tracheal aspirate (21), blood (15); tissue/wound/drainage (13) and urine samples (2) were collected. Colistin appeared to be the most effective agent with 98% in vitro activity. MHT showed 98% positivity, MBLs production was detected in 94.1% isolates and 64.7% were positive for AmpC β-lactamase production. All 15 isolates carried blaOXA-23 and blaVIM, of these 3 also carried blaNDM gene. Colistin containing combinations were more commonly used (68.3%). Colistin-noncarbapenem combination showed improved clinical response compared to colistin-carbapenem combination against Acinetobacter isolates carrying blaOXA-23 and blaVIM.Conclusion: A stringent infection control practice along with antimicrobial stewardship is needed to prevent emergence of Acinetobacter carrying multiple carbapenemase genes along with blaNDM. Various colistin combinations are preferentially used to treat CR-Ab infections. Identification of antimicrobial combinations with proven in vitro activity that encompass local susceptibility patterns as well as molecular mechanisms of resistance is needed to provide better outcome.Keywords: Acinetobacter baumannii, Carbapenem resistance, Carbapenemases, Colistin combination, metallo-β-lactamase, NDMÂ
Study on Basic Mechanism of Reactive Armour
Two basic mechanisms which operate in the functioning of reactive armour are presented. Both the explosive effect and cutting of metal plates by a jet have been investigated. The angle of attack and the confinement of the explosive have been found most significant factors in reducing the penetrating power of the jet. The effect of detonating explosives has been investigated with radiography. Some of the significant effects, like detonation of explosive by the impact of the jet, expansion of covering plates, disturbance in coherence and reduction in the penetration of the jet have been observed. It is found that the jet penetration in a stack of mild steel plates is reduced to 30 per cent of its blank penetration in present set-ups. A theoretical model has been conceived to study the interaction of moving plates and the jet. The critical thickness and surface cut in plates have been calculated
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