Application of synthetic solid culture medium to improve the detection of antimicrobial drug residues in foodstuffs

A selective synthetic solid minimal medium (BS agar) was developed to detect antimicrobial drug-residues in foodstuffs using Bacillus subtilis indicator culture. This medium contains an ammonium salt as nitrogen source and either glucose or sodium pyruvate as carbon sources.Its selectivity is based on the fact that Bacillus subtilis is still able to grow if the minimal medium consists of simple inorganic substances as nitrogen sources, and glucose or pyruvate as carbon supply. Using these new synthetic media for microbiological assays assessing certain antimicrobials, the diameter of the inhibition zones were 1.4–4 times wider than on the Mueller-Hinton agar.The advantages of the BS agars are their standard compositions, the absence of inhibitors, the reproducible quality and the low costs

Synthetic Culture Media Evaluated for the Detection of Coliform Bacteria in Milk, Cheese and Egg Melange

Simple synthetic culture media of liquid and solid form (X broth and X agar) were tested for selective isolation of coliform bacteria. Selectivity is based on the ability of coliform bacteria to grow when the minimal medium contains simple inorganic substances as nitrogen and carbon supply. Selectivity of the media was tested by inoculation of pure cultures of different microbes belonging to the genera of Staphylococcus, Bacillus and Pseudomonas and the family Enterobacteriaceae and was found to be complete in this range. The comparative investigation of milk, camembert cheese and egg melange samples in the traditional and new media proved good applicability of X broth and X agar for an effective and selective detection of coliform bacteria. When testing pasteurized milk samples, X agar detected coliforms in significantly higher counts than violet red-bile-lactose agar

Effect of Polarized Light Treatment on Milk Production and Milk Somatic Cell Count of Cows

Treatment with linearly polarized light (LPL) is a widely used and recognized therapeutic method in human medicine for healing wounds, ulcers and a variety of other dermatological problems. Polarized light mobilizes the inadequately functioning defence mechanisms of the human body. The aim of the present experiment was to investigate the effect of LPL treatment on the udder of milking cows. Before the start of treatment, there was no significant difference between cows to be treated with LPL and the control cows in mean somatic cell counts (SCC) of milk samples taken separately by udder quarter and in the mean milk yield. The LPL treatment lasted for 20 min and was performed twice a day over a period of one month. Before treatment, the mean SCC of milk was 3.47 × 105 ± 910 in the group to be treated and 4.07 × 105 ± 920 in the control group. In a six-week period immediately after treatment, the mean SCC of the treated and the control group was 1.32 × 105 ± 825 and 2.63 × 105 ± 825, indicating a significant difference in favour of the treated group. Before the LPL treatment, the milk yield of cows in the group to be treated was 25.77 ± 1.2 kg/ day, while that of the control cows was 27.30 ± 1.4 kg/day. In a six-week period after treatment, the milk yield of cows in the treated and control groups was 28.83 ± 1.5 kg/day and 25.48 ± 1.4 kg/day, respectively. There is a significant difference between these values in favour of the treated group. The results show that a regular LPL treatment of the udder of cows can significantly reduce the SCC of milk and significantly increase the milk yield. The treatment can be applied during lactation without interfering with the milking regime

The Double Star Plasma Electron and Current Experiment

The Double Star Project is a collaboration between Chinese and European space agencies, in which two Chinese magnetospheric research spacecraft, carrying Chinese and European instruments, have been launched into equatorial (on 29 December 2003) and polar (on 25 July 2004) orbits designed to enable complementary studies with the Cluster spacecraft. The two Double Star spacecraft TC-1 and TC-2 each carry a Double Star Plasma Electron and Current Experiment (PEACE) instrument. These two instruments were based on Cluster Flight Spare equipment, but differ from Cluster instruments in two important respects. Firstly, a Double Star PEACE instrument has only a single sensor, which must be operated in a manner not originally envisaged in the Cluster context in order to sample the full range of energies. Secondly, the DPU hardware was modified and major changes of onboard software were implemented, most notably a completely different approach to data compression has been adopted for Double Star, which allows high resolution 3-dimensional distributions to be transmitted almost every spin, a significant improvement over Cluster. This paper describes these instruments, and includes examples of data collected in various magnetospheric regions encountered by the spacecraft which have been chosen to illustrate the power of combined Double Star and Cluster measurements

Culturing Aerobic and Anaerobic Bacteria and Mammalian Cells with a Microfluidic Differential Oxygenator

In this manuscript, we report on the culture of anaerobic and aerobic species within a disposable multilayer polydimethylsiloxane (PDMS) microfluidic device with an integrated differential oxygenator. A gas-filled microchannel network functioning as an oxygen−nitrogen mixer generates differential oxygen concentration. By controlling the relative flow rate of the oxygen and nitrogen input gases, the dissolved oxygen (DO) concentration in proximal microchannels filled with culture media are precisely regulated by molecular diffusion. Sensors consisting of an oxygen-sensitive dye embedded in the fluid channels permit dynamic fluorescence-based monitoring of the DO concentration using low-cost light-emitting diodes. To demonstrate the general utility of the platform for both aerobic and anaerobic culture, three bacteria with differential oxygen requirements (E. coli, A. viscosus, and F. nucleatum), as well as a model mammalian cell line (murine embryonic fibroblast cells (3T3)), were cultured. Growth characteristics of the selected species were analyzed as a function of eight discrete DO concentrations, ranging from 0 ppm (anaerobic) to 42 ppm (fully saturated)

Observations of large-amplitude, parallel, electrostatic waves associated with the Kelvin-Helmholtz instability by the magnetospheric multiscale mission

On 8 September 2015, the four Magnetospheric Multiscale spacecraft encountered a Kelvin-Helmholtz unstable magnetopause near the dusk flank. The spacecraft observed periodic compressed current sheets, between which the plasma was turbulent. We present observations of large-amplitude (up to 100 mV/m) oscillations in the electric field. Because these oscillations are purely parallel to the background magnetic field, electrostatic, and below the ion plasma frequency, they are likely to be ion acoustic-like waves. These waves are observed in a turbulent plasma where multiple particle populations are intermittently mixed, including cold electrons with energies less than 10 eV. Stability analysis suggests a cold electron component is necessary for wave growth