An Efficient Isocyanide-Based Three-Component Synthesis of Novel Ketenimines

This study provides a description of an efficient and simple procedure for the synthesis of dimethyl 2-(9-aryl)-3,3,6,6-tetramethyl-1,8-diox-1,2,3,4,5,6,7,8-octahydroacridin-10(9H)-yl)-3-((cyclohexylimino)methylene)succinate via a one-pot three-component reaction of cyclohexyl isocyanide, dimethyl acetylenedicarboxylate and hexahydroacridine-1,8(2H,5H)-dionesin CH2Cl2 at room temperature. Short reaction times, good to high yields and the novelty are the remarkable advantages of this work

Immobilization of Phytase Producing Probiotics in Shrimp Chitosan Cross-linked by Zinc Oxide Nanoparticles and Assay its Antibacterial Activity

Background and objective: Phytase is used in human and poultry additives. This enzyme is mostly produced by Aspergillus niger which is a plant pathogen. Phytase from probiotics is a good candidate for the food supplements.Materials and methods: Bacillus coagulans, as a probiotic, was used for phytase and phosphatase activities on phytin agar and Pikovskayas Agar. The sodium dodecyl sulfatepolyacrylamide gel electrophoresis and zymogram analyses of the extracted phytase enzyme were carried out. Probiotic cells with phytase activity were immobilized on chitosan extracted from shrimp shells and the efficiency was investigated and analyzed using scanning electron microscopy and Fourier transform infrared.Results and conclusion: In this study, Bacillus coagulans showed intracellular phytase activities from broken cells with Soluble Index of 2.5 on phytase specific media. Iron and zinc oxide nanoparticles accelerated the enzyme activity by 25%. Cells were precipitated using ZnO-chitosan nanoparticles and the enzyme activity was investigated on gels. Chelation of chitosan-metal ion increased the positive charge density of chitosan which was expected to enhance adsorption of zinc and teichoic acid on Gram-positive Bacillus coagulans; approved by SEM and FTIR. Cells immobilized on ZnO-chitosan promoted the enzyme activity by 28,800 U ml-1 gel. The entrapped cells were resistance to high temperature and pH. This complex not only included activities against Streptococcus agalactiae, but also dissolved insoluble phosphate and phytin, which has made this complex a good candidate for use as additive in human and animal foods.Conflict of interest: The authors declare no conflict of interest

Antimicrobial, heavy metal resistance and plasmid profile of coliforms isolated from nosocomial infections in a hospital in Isfahan, Iran

The antimicrobial, heavy metal resistance patterns and plasmid profiles of Coliforms (Enterobacteriacea) isolated from nosocomial infections and healthy human faeces were compared. Fifteen of the 25 isolates from nosocomial infections were identified as Escherichia coli, and remaining as Kelebsiella pneumoniae. Seventy two percent of the strains isolated from nosocomial infections possess multiple resistance to antibiotics compared to 45% of strains from healthy human faeces. The difference between minimal inhibitory concentration (MIC) values of strains from clinical cases and from faeces for four heavy metals (Hg, Cu, Pb, Cd) was not significant. However most strains isolated from hospital were more tolerant to heavy metal than those from healthy persons. There was no consistent relationship between plasmid profile group and antimicrobial resistance pattern, although a conjugative plasmid (>56.4 kb) encoding resistance to heavy metals and antibiotics was recovered from eight of the strains isolated from nosocomial infections. The results indicate multidrug-resistance coliforms as a potential cause of nosocomial infection in this region. Key words: Nosocomial infection, plasmid profile, antimicrobial resistance, Escherichia coli, Kelebsiella pneumoniae. African Journal of Biotechnology Vol.2(10) 2003: 379-38

Comparison of Bacterial Cellulose Production among Different Strains and Fermented Media

The effect of different carbon sources on bacterial cellulose production by Gluconacetobacter xylinus (PTCC 1734) and two newly isolated strains (from vinegar) under static culture conditions was studied. The production of bacterial cellulose was examined in modified Hestrin-Shramm medium by replacing D-glucose with other carbon sources. The results showed that the yield and characteristics of bacterial cellulose were influenced by the type of carbon source. Glycerol gave the highest yield in all of the studied strains (6%, 9.7% and 3.8% for S, A2 strain and Gluconacetobacter xylinus (PTCC 1734), respectively). The maximum dry bacterial cellulose weight in the glycerol containing medium is due to A2 strain (1.9 g l-1) in comparison to Gluconacetobacter xylinus as reference strain (0.76 g l-1). Although all of the studied strains were in Gluconacetobacter family, each used different sugars for maximum production after glycerol (mannitol and fructose for two newly isolated strains and glucose for Gluconacetobacter xylinus). The maximum moisture content was observed when sucrose and food-grade sucrose were used as carbon source. Contrary to expectations, while the maximum thickness of bacterial cellulose membrane was attained when glycerol was used, bacterial cellulose from glycerol had less moisture content than the others. The oxidized cellulose showed antibacterial activities, which makes it as a good candidate for food-preservatives

The relative effects of some elements on the DNS method in cellulase assay

For evaluating the relative effects of some polluting salts on the measurement of cellulase activity assayed by 3,5-dinitrosalicylate (DNS) this study was done. Glucose and cellulase solutions have been treated with salts. Exoglucanase and endoglucanase were assayed by 3,5-dinitrosalicylate reagent. Measurement of reducing sugar by DNS indicator in the presence of Ca+2, Ba+2, Fe+3, Mn+2, Pb+2, Fe+2, Ag+1, Zn+2, Co+2, and Al+3 salts overestimated and in the presence of Mg+2, Cu+2, Cd+2, and Hg+2 salts underestimated the real contents. The intensity of DNS color and/or the reducing power of glucose increased by decreasing radius of hydrated cation of alkaline-earth elements (from Mg+2 to Ba+2) in glucose solution. Exoglucanase and endoglucanase activities increased in the presence of Na+, K+, Ca+2, Ba+2 and Mn+2 salts and decreased in the presence of NH4 + and Mg+2 salts. Among the trace elements studied, Fe+3, Pb+2, Fe+2, Ag+1, Zn+2, Co+2, and Al+3 were the most effective inhibitors of cellulase activity. These ions inhibited exoglucanase more than endoglucanase. The effect of most ions on cellulase activity may be related to negative or positive effect of them on the method of cellulase assessment. So, for a better data interpretation in the study of ion effects on the soil enzyme activity, both the effects of ions on the method of enzyme assay, and the effects of ions on the enzyme activity should be studied. Journal of Applied Sciences and Environmental Management Vol. 10(3) 2006: 93-9

Preparation of a Microbial Time-temperature Indicator by Using the Vegetative Form of Bacillus amyloliquefaciens for Monitoring the Quality of Chilled Food Products

Background and Objective: Time-temperature indicators are used in smart packaging, and described as intelligent tools attached to the label of food products to monitor their timetemperature history. Since the previous studies on microbial time-temperature indicators were only based on pH-dependent changes, and they were long-time response indicators, in the present work, a new microbial time-temperature indicator was designed by using the alpha amylase activity of Bacillus amyloliquefaciens vegetative cells.Material and Methods: The designed time-temperature indicator system consists of Bacillus amyloliquefaciens, specific substrate medium and iodine reagent. The relation of the timetemperatureindicator’ response to the growth and metabolic activity (starch consumption and production of reduced sugars) of Bacillus amyloliquefaciens was studied. In addition, the temperature dependence of the time-temperature indicator was considered at 8 and 28˚C. Finally, in order to adjust time-temperature indicator endpoint, the effect of the inoculum level was investigated at 8ºC.Results and Conclusion: In the designed system, a color change of an iodine reagent to yellow progressively occurs due to the starch hydrolysis. The effect of the inoculum level showed the negative linear relationship between the levels of Bacillus amyloliquefaciens inoculated in the medium and the endpoints of the time-temperature indicators. The endpoints were adjusted to 156, 72 and 36 hours at the inoculum levels of 102, 104 and 106 CFU ml-1, respectively. The main advantages of the time-temperature indicator is low cost and application for monitoring the quality of chilled food products.Conflict of interest: The authors declare no conflict of interest

Biodegradation of some agricultural residues by fungi in agitated submerged cultures

Digestibility of agricultural residues in animal feeding is deeply dependent on the amounts and types of their fibers. Biological treatment of agricultural residues is a new method for improvement of digestibility. Therefore, the capacity of a few fungi in biodegradation of some agricultural residues wasstudied. Losses of crude fiber (CF), neutral detergent fiber (NDF) and acid detergent fiber (ADF) of wheat, barley, rice, wood, and pea straw were investigated in agitated submerged culture during biodegradation by fungi. Biodegradation of the plant residues is dependent on the plant and fungusspecies. The biodegradation order of plant residues was  pea>barley>wheat>rice>wood. A. terreus and T. reesei were more able to degrade the easy degradable plant residues. Rice and wood were degradedmore by Armillaria sp., Polyporus sp. and P. chrysosporium. Crude fiber, NDF and ADF of agricultural residues were reduced more by P. chrysosporium. Generally, the reduction of agricultural residues NDF by fungi was more than their ADF. However, Polyporus sp. decreased ADF of wheat straw more. Thus, for improvement of digestibility of agricultural residues, the treatment by white-rot fungi may be recommended

Isolation and Identification of Alicyclobacillus with High Dipicolinic Acid and Heat Resistant Proteins from Mango Juice

Background and Objectives: Microbial spoilage of juices and industries related with Alicyclobacillus are considerable international issues. This spore-forming bacterium causes changes in juices odor and taste. The isolation and identification of Alicyclobacillus contamination in juice producing and packaging industries has an essential role in the prevention and control of this type of spoilage bacterium in HACCP (Hazard analysis and critical control points ) manner.Materials and Methods: A thermo-acidophilic, non-pathogenic and sporeforming bacterium was isolated from mango juice. Preliminary identification of the isolates was based on morphological, biochemical and physiological properties. Identification at species level was made by PCR amplification. The influence of temperature in the range of 25-65°C in the growth of bacterium and in the range of 80-120°C in spore-resistant and heat resistant proteins was investigated and compared with other spore producing bacteria.Results and Conclusion: Phylogenetic analysis of the 16S rRNA gene sequencing indicated that the isolated strain constituted a distinct lineage in the Alicyclobacillus cluster and submitted to NCBI with access number Alicyclobacillus HRM-5 KM983424.1. The spores resisted 110°C for 3 h, and produced 28% dipicolinic acid more comparable to Bacillus licheniformis. Also they could produce 0.69 mg heat resistance protein after 1.5 h treatment in 100°C. The results showed that this strain could have biotechnological applications.Conflict of interests: The authors declare no conflict of interest

Biosynthesis of Nano-Calcite and Nano-Hydroxyapatite by the Probiotic Bacteria of Bacillus subtilis and Bacillus coagulans

Background and objective: In recent years, the green synthesis of nanomaterials has received more attention than chemical synthesis due to its eco-friendly and compatibility. Material and methods: In this study Bacillus subtilis and Bacillus coagulans, two potential probiotics, were used and grown Bacillus in medium culture containing insoluble calcium phosphate produced nano-hydroxyapatite and nano-calcite. The nano-hydroxyapatite was purified from nano-calcite by heat treatment and washing with a 200 nm filter. The structures, characteristics, and elemental analysis of nano-sized material were studied by Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscope, ultraviolet-visible spectroscopy, energy dispersive X-ray, and X-ray fluorescence. Results: The results showed that hydroxyapatite is made only in a medium containing insoluble calcium phosphate sublimated with urea which is induced phosphatase and urease. Here, for the first time, the braided bacterial nano-hydroxyapatite similar to the bone structure was made in the medium, which caused the production of urease and phosphatase (Maximum 99 U/L) enzymes, and the particle size was less than 100 nm. The ratio of calcium to phosphorus in crude hydroxyapatite and calcite crystal particles made by B. coagulans was 2.9, however, this ratio for pure hydroxyapatite was 1.7. Conclusion: Since the particles are made by antibacterial probiotics, the biological production of these particles makes them a suitable candidate to be used in food, toothpaste, and sanitation products. Braided hydroxyapatite can substitute the needle-like type of food additives for infants and elders due to its safety

Utilization of petroleum hydrocarbons by Pseudomonas sp. and transformed E. coli

Our previous studies showed that the biodegradation of petroleum oil by a i>pseudomonas isolated from a petroleum-contaminated soil was instable. In this work, t is shown that when the isolates are immobilized on Perlite, they are more stable for oil egradation. Although the isolate did not have any chemotaxis to octadecane, dodecane and ctane but utilize octadecane and dodecane better than octane and it did not utilized exane, benzene, kerosene, pentane, heptane or thiophenol. The generation time for degradation of petroleum oil, dodecane and octadecane was 20, 22, and 25 h respectively. This phenotype was not transformed to Pseudomonas by conjugation even with lysozyme treatment, however the petroleum oil and octadecane utilization were transformed to E. coli by lysozyme treatment. The transformed E. coli lost the ability to use octadecane after three subcultures on nutrient broth and 34 generations.African Journal of Biotechnology Vol. 4 (2), pp. 172-176, 200