Surface growth of Escherichia coli cells on a membrane filter placed on a nutrient agar plate under various conditions was studied with a mathematical model. The surface growth of bacterial cells showed a sigmoidal curve with time on a semilogarithmic plot. To describe it, a new logistic model that we presented earlier (H. Fujikawa et al., Food Microbiol. 21:501-509, 2004) was modified. Growth curves at various constant temperatures (10 to 34°C) were successfully described with the modified model (model III). Model III gave better predictions of the rate constant of growth and the lag period than a modified Gompertz model and the Baranyi model. Using the parameter values of model III at the constant temperatures, surface growth at various temperatures was successfully predicted. Surface growth curves at various initial cell numbers were also sigmoidal and converged to the same maximum cell numbers at the stationary phase. Surface growth curves at various nutrient levels were also sigmoidal. The maximum cell number and the rate of growth were lower as the nutrient level decreased. The surface growth curve was the same as that in a liquid, except for the large curvature at the deceleration period. These curves were also well described with model III. The pattern of increase in the ATP content of cells grown on a surface was sigmoidal, similar to that for cell growth. We discovered several characteristics of the surface growth of bacterial cells under various growth conditions and examined the applicability of our model to describe these growth curves.
- American Society for Microbiology
- Modeling surface growth of escherichia coli on agar plates
Filters for the Filter Manufacturer
Filtration systems for manufacturing often require high-purity filters to remove contaminants from water, liquids or gases, as well as to optimize production and meet quality standards. The right filters and housing greatly affect production outcomes, and can help reduce costs and protect equipment along the way. With this in mind, Shelco Filters put its own products to the test when it built a new pleated cartridge manufacturing facility at its Middletown, Conn., headquarters. This move required Shelco to...
MAS Introduces Filter Innovation
Our partner MAS has recently attracted attention for a range of technical innovations in extrusion and plastic recycling technology, including the co-rotational conical twin screw extruder and a waterless cleaning system for film flakes. This year, at the FAKUMA exhibition in Germany, MAS introduced further technical developments with a range of patent-protected continuous melt filtration systems available in three power levels for flow rates of from 300 to 2,000 kg/h. The MAS Filter Innovation The objective of...
Size reduction of filter cakes with the Gericke Nibbler
Application: Separating solids from a suspension by filtering, centrifuging or drying. Then shredding of the filter cake. Process: The suspension is pumped into the press. The solid particles are deposited on the filter medium and form filter cakes on the filter plates. To press as much liquid as possible out of the filter cake, the plates are compressed at high pressure by a hydraulic press. The modular design of the filter presses can provide filter areas from 1 to 1000 m2 in area. The compressed filter...
Diazinon plate statfax 303+ program set-up
General Comments:This technical bulletin is a guide for the installation of the Diazinon Plate Kit Protocol onto the StatFax 303 Plus Microwell photometer. Please refer to the StatFax 303 Plus User’s Manual for detailed instructions. Bold lettering indicates the StatFax screen display. [Brackets] denote keys. Protocol:1. Turn on the StatFax 303 Plus.2. Press the [MULT] key on the keypad.3. Regression Y/N: Press the [Yes] key.4. Filter Selection: Press  key for 450nm, then [Enter]5. Diff Filter Selection:...
Microcystins plate statfax 303+ program set-up
General Comments:This technical bulletin is a guide to the installation of Microcystins Plate Kit Protocol into the StatFax 303 Plus. Please refer to the StatFax 303 Plus Manual for detailed instructions. Bold lettering indicates the StatFax screen display. Protocol1. Turn on the StatFax 303 Plus.2. Press the [MULT] key on the keypad.3. Regression Y/N: Press the [Yes} key.4. Filter Selection: Press  key for 450nm, then [Enter]5. Diff Filter Selection: Press  key for no filter, then [Enter]6. Offset Abs...