31 results about "Most probable number" patented technology

Methods and compositions are disclosed for confirming and quantifying the presence of a specific probiotic microorganism in a sample of animal feed. Hybridization and polymerase chain reaction (PCR) techniques are applied to identify the presence of the specific probiotic microorganism in cultures grown in most probable number and serial dilution methods, after calibration of the techniques using blank and control samples.

Methods and compositions are disclosed for confirming and quantifying the presence of a specific kind of microorganism in a sample of material. Hybridization and polymerase chain reaction (PCR) techniques are applied to identify the presence of the specific microorganism in cultures grown in most probable number and serial dilution methods, after calibration of the techniques using blank and control samples. For example, samples of animal feed can be cultured and analyzed to determine the quantity of specific probiotic microorganisms present in the feed.

A precise quantization method for nitrogen cycle of a lake ecosystem includes 1), applying an isotope pairing method to quantitatively research nitrogen migration and conversion of a sediment-water interface of the lake ecosystem; 2), determining release of nitrogen of a water-gas interface by measuring N2O yield by the aid of a closed chamber-gas chromatograph method; 3), measuring biomass of aquatic plants and nitrogen content in bodies of the aquatic plants by the aid of a Dumas method and determining nitrogen absorbed quantity of the aquatic plants; 4), measuring biomass of microorganisms in the ecosystem by the aid of an MPN (most probable number) method, and measuring the effect of the microorganisms in a nitrogen conversion process and conversion quantity of the microorganisms to the nitrogen; and 5), applying the stable isotope technology to measure assimilation of aquatic animals to the nitrogen, and realizing precise quantization of the nitrogen, namely, measuring a food web of the aquatic animals and a trophic-level structure to determine migration and conversion of the nitrogen in the food web. Procedures of the precise quantization method are realized in the same simulation ecosystem.

The invention discloses a coliform single-tube quantitative rapid detection method which comprises the steps: preparing specific detection culture medium; inoculating sample; culturing the inoculated sample for 8-15h at the temperature of 35-44DEG C; centrifugating for 5-10min at the speed of 8000-12000rpm; measuring absorbance value at the part of 405nm of supernate by a spectrophotometer; and calculating bacteria concentration according to formula. The method utilizes the spectrophotometer to measure the absorbance value of culture solution, and is more sensitive than visual evaluation, thus greatly shortening the culturing time. By adopting the single-tube quantitative detecting technique, one simple needs a tube of culture solution, so that a great deal of reagent and consumable materials can be saved compared with most probable number method; furthermore, the detection method is more rapid and stabler, and has high sensitivity.

Methods and compositions detect and quantify viable Legionella. Dip-slides that include an absorbent medium, growth promoting, and growth selective substances are useful in rapid detection and quantification of microcolonies of Legionella. Most probable number method of detection and quantification of Legionella are disclosed.

The invention discloses a quantiative detection method of salmonella in soil and an assay kit thereof. On the basis of taking related researches as reference, the method performs quantitative detection on pathogenic microorganism in the soil by adopting a method of combining MPN (most probable number) with PCR (polymerase chain reaction). By utilizing advantages of quickness and accuracy of the PCR method, biochemical identification, serological identification and other steps of positive results in the traditional MPN method are substituted, so that complex steps in a national standard methodare reduced, the detection efficiency is improved, and a pre-enrichment step in the national standard method is adopted at the same time to improve the accuracy of detection targeting pathogenic bacteria; and due to the complexity of soil, the soil contains massive microorganisms, as well as various pathogenic microorganisms of different items, so that the targeting pathogenic bacteria is selectively cultured to improve the detection efficiency in order to quantitatively detect the targeting pathogenic bacteria better and more accurately. By virtue of creative effort of the inventor and scientific test verification, the sensitivity of the salmonella quantitative detection method in an experiment of adding pure bacteria in the soil is 250 per gram of soil.

The invention discloses a quantitative detection method of salmonella living body in water, which adopts a multiple-tube fermentation method to preliminarily screen living bacteria taking salmonella as the principal component from water sample according to the growth characteristics of the salmonella and the conservative property of invA gene. By utilizing universal primers 139 and 141 of the salmonella, the quantitative detection method can be used for distinguishing the positive colony of the salmonella by polymerase chain reaction (PCR) amplification. The quantitative detection method can be used for detecting the salmonella living body in water in a quantitative way by a most probable number (MPN) counting method. The method can accurately detect the content of the salmonella living body in water, is high in specificity as well as simple and convenient to operate, and is suitable for detecting multiple water samples such as surface water, sewage and the like.

The invention discloses a quantiative detection method of escherichia coli in soil and an assay kit thereof. On the basis of taking related researches as reference, the method performs quantitative detection on pathogenic microorganism in the soil by adopting a method of combining MPN (most probable number) with PCR (polymerase chain reaction). By utilizing advantages of quickness and accuracy ofthe PCR method, biochemical identification, serological identification and other steps of positive results in the traditional MPN method are substituted, so that complex steps in a national standard method are reduced, the detection efficiency is improved, and a pre-enrichment step in the national standard method is adopted at the same time to improve the accuracy of detection targeting pathogenic bacteria; and due to the complexity of soil, the soil contains massive microorganisms, as well as various pathogenic microorganisms of different items, so that the targeting pathogenic bacteria is selectively cultured to improve the detection efficiency in order to quantitatively detect the targeting pathogenic bacteria better and more accurately. By virtue of creative effort of the inventor andscientific test verification, the sensitivity of the escherichia coli quantitative detection method in an experiment of adding pure bacteria in the soil is 25 per gram of soil.