ABSTRACT
Aims@#Attention to ice nucleation proteins has increased for more than two decades. Ice nucleation proteins have been utilized for artificial snow-making known as Snowmax™, cryopreservation of tissues and cells, and cloud condensation nuclei. There is a direct relationship between bacterial growth and ice nucleation activity. Therefore, the optimization of the culture medium seems necessary.@*Methodology and results@#The effect of different carbon and nitrogen sources on the growth of a new native Pseudomonas sp. IRL.INP1 was evaluated by using fractional factorial design, the path of the steepest ascent experiment and central composite design. Ice nucleation activity, biomass and whole-cell protein were identified afterward. The model predicted by response surface methodology indicated that the maximum bacterial growth was observed when sucrose, ammonium sulfate [(NH4)2SO4] and manganese (II) (Mn2+) were utilized at 12.46 g/L, 321.97 mg/L and 938.09 µM, respectively. Also, 1.10 g/L biomass and 0.85 µg/µL whole-cell proteins were gained, and the isolate showed ice nucleation activity 31 sec sooner after optimization.@*Conclusion, significance and impact of study@#Ice nucleation proteins are growth-dependent and the growth condition optimization leads to higher bacterial cells growth. Therefore, best bacterial growth was obtained when proper carbon and nitrogen sources were used, and ice nucleation activity was observed in shorter time. This is the first study concerning ice nucleation activity optimization using different carbon and nitrogen sources.
Subject(s)
PseudomonasABSTRACT
Pseudomonas aeruginosa is a common hospital-acquired bacterium which has ability to produce fluorescent pigment like pyorubin and nonfluorescent pigment like pyocyanine. The aim of this study was exciting of production of pyoverdin pigments as biomarker for quick detection of this bacterium in foods and hygienic products. In this research, different concentrations of cadmium sulfate were used for showing the exciting of pyoverdin pigments. Pigment type was evaluated according to the maximum absorbance and its solubility in water, acetic acid and chloroform. Also, bacterium growth pattern was determined according to pigment production in optimal conditions of agitation, temperature, cultivate media, sources of carbon and nitrogen. Relation between pigment production and number of bacteria was calculated by absorbance and cell accumulation. Bacteria tracking was investigated using pigment production as biomarker in foods [spaghetti and apple juice] and hygienic products [hand and dish washing liquids] and compared to standard method. This study showed maximum absorbance of extracted pigment at 403 nm and its solubility in water and acetic acid. Production of fluorescent pigment in bacterium was observed at concentrations 0.3-0.5 mM of cadmium sulfate. Maximum production of florescent pigments based on cell accumulation was established by agitation in 150 rpm, temperature of 35oC, 0.5 mM solution of cadmium and concentration of 330 mgml-1of 1% sucrose and potassium nitrate. Monitoring of Pseudomonas aeruginosa in contaminated foods and hygienic products based on fluorescent pigments production was reduced from 72 to 20 hours
ABSTRACT
Nowadays, cancer is one of the main causes of mortality in the world and many mutagens are the cause of death in millions of patients. Due to the side effects of anticancer drugs, scientists are in search of natural drugs with fewer side effects and more therapeutic efficacy. This study aims to, firstly, investigate the antimutgenic effects of different Aloe vera gel and latex extracts on mutated Salmonella typhimurium bacterium by using Ames test and to, secondly, study the probable effects of the habitat conditions on the antimutagenic effects of the plant. After preparing different Aloe vera gel and latex extracts, the antimutagenic effects of the extracts were evaluated by Ames test. In this test, a mutated strain of S. typhimurium was grown on culture media containing a minimum of salt and glucose in the presence of a mutagen substance [NaN3]. Subsequently, only those bacteria that had turned HIS+ by reverse mutation formed colonies. As different alcoholic and aqueous extracts of Aloe vera reduced reversed mutations, the difference between the means of revertant mutants per plate was calculated by one-way ANOVA using SPSS software [version 18]. The ethanol extracts of latex from Karaj had a maximum [91%] and aqueous extract from Dezfoul had a minimum [42%] percentage of inhibition. Maximum percentage of inhibition was observed in the extracts of the plant cultivated in Karaj reflecting the impact of environmental conditions on the construction of antioxidant compounds in plants
ABSTRACT
Chemical carcinogens may be produced by metabolic activity of microbes residing in gastrointestinal system. Researches suggest that the consumption of probiotic cultures may decrease the risk of cancer. The aim of this study was to evaluate inhibitory effects of probiotic cultures on mutant and cancerous cells. In this experimental study, antimutagenic effects of probiotic cultures, including Bifidobacterium bifidus. Bifidobacterium longum, Lactobacillus acidophilus, Lactobacillus bulgaricus, Lactobacillus rhammosus and Streptococcus thermophillus, were assessed by the Salmonella/microsome assay upon sodium azid and nitrosamine by Ames test. There were anticancer and antimutagenic activities of probiotic cultures. Anticarcinogenic effects of probiotic cultures were mostly above 40% representing their potent anticarcinogenic activities. This study showed that probiotic cultures have potent anticarcinogenic and antimutagenic activities