Bacteria Cells (bacteria + cell)

Distribution by Scientific Domains


Selected Abstracts


The balance between photosynthesis and grazing in Antarctic mixotrophic cryptophytes during summer

FRESHWATER BIOLOGY, Issue 11 2002
William Marshall
SUMMARY 1. Grazing and photosynthetic contributions to the carbon balance of planktonic, mixotrophic cryptophytes in Lakes Fryxell and Hoare in the Taylor Valley, Antarctica were measured during November and December 2000. 2. The cryptophytes never became entirely photosynthetic, although carbon derived from grazing decreased in December. Individual grazing rates ranged between 5.28 and 10.08 bacteria cell,1 day,1 in Lake Fryxell and 0.36,11.76 bacteria cell,1 day,1 in Lake Hoare. Grazing rates varied temporally and with depth in the water column. In Lake Fryxell, which is a meromictic lake, highest grazing occurred just above the chemocline. Individual photosynthetic rates ranged from 0.23 to 1.35 pg C cell,1 h,1 in Lake Fryxell and 0.074 to 1.08 pg C cell,1 h,1 in Lake Hoare. 3. Carbon acquisition by the cryptophyte community gained through grazing ranged between 8 and 31% during November in Lake Fryxell, dropping to between 2 and 24% in December. In Lake Hoare grazing contributed 12,21% of the community carbon budget in November and 1,28% in December. Around 4% of the carbon acquired from grazing and photosynthesis was remineralised through respiration. 4. Mixotrophy is probably a major survival strategy for cryptophytes in the extreme lakes of the Dry Valleys, because perennial ice-cover severely limits light penetration to the water column, whereas these phytoflagellates are not normally mixotrophic in lower latitude lakes. The evidence suggests that mixotrophy may be a mechanism for supplementing the carbon budget, as well as a means of acquiring nutrients for growth. [source]


Monolithic Ceramic Foams for Ultrafast Photocatalytic Inactivation of Bacteria

JOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 8 2009
Pinggui Wu
Palladium-modified nitrogen-doped titanium dioxide (TiON/PdO) foams were synthesized by a sol,gel process on a polyurethane foam template. The TiON/PdO foam was tested for microbial killing using Escherichia coli cells as a target. Under visible-light illumination, the TiON/PdO foam displayed a strong antimicrobial effect on the bacteria cells in water. The antimicrobial effect was found to be dependent on the palladium content and the calcination temperature. In a flow-through dynamic photoreactor, the new photocatalyst efficiently inactivated E. coli within a short contact time (<1 min), the shortest ever reported for the photocatalytic killing of bacteria. The strong antimicrobial functions of the TiON/PdO foam were related to charge trapping by PdO and the high contact efficiency of the foam structure. [source]


Effects of the commercial probiotic Lactobacillus casei on the growth, protein content of skin mucus and stress resistance of juveniles of the Porthole livebearer Poecilopsis gracilis (Poecilidae)

AQUACULTURE NUTRITION, Issue 4 2010
L.H.H. HERNANDEZ
Abstract A 11-week feeding trial was carried out to determine the effects of the probiotic bacteria Lactobacillus casei from the commercial product Yakult® on the growth performance, proximal composition, protein content of skin mucus and stress resistance of juvenile Porthole livebearer Poeciliopsis gracilis. Triplicate groups of 15 juveniles per tank with an initial weight of 47 ± 9 mg (mean ± standard deviation) were fed with Artemia nauplii enriched with the probiotic, by using the bacteria cells plus the fermented milk (group ProN) and the other (group ProC) by using only the bacterial cells, eliminating the fermented milk by centrifugation. A control of fish was set up, by feeding non-enriched Artemia nauplii. Growth performance and survival rates did not show significantly differences among the treatments and control group, but a slightly tendency of higher values for body weight, weight gain and specific growth rate was observed in the juveniles of ProC treatment. Whole body proximate composition did not show significant differences among the groups, but higher values of protein and lipid contents were observed in the groups fed with the probiotic. Content of protein in the skin mucus were significantly higher in the ProC treatment than control group. Recovery rates after an air-dive test were significantly higher on the fish fed with the probiotic cells than the control group. These results show that L. casei might be used as a probiotic for fish and would help during the culture of juvenile of the Porthole livebearer P. gracilis. [source]


Continuous scalable blood filtration device using inertial microfluidics

BIOTECHNOLOGY & BIOENGINEERING, Issue 2 2010
Albert J. Mach
Abstract Cell separation is broadly useful for applications in clinical diagnostics, biological research, and potentially regenerative medicine. Recent attention has been paid to label-free size-based techniques that may avoid the costs or clogging issues associated with centrifugation and mechanical filtration. We present for the first time a massively parallel microfluidic device that passively separates pathogenic bacteria cells from diluted blood with macroscale performance. The device was designed to process large sample volumes in a high-throughput, continuous manner using 40 single microchannels placed in a radial array with one inlet and two rings of outlets. Each single channel consists of a short focusing, gradual expansion and collection region and uses unique differential transit times due to size-dependent inertial lift forces as a method of cell separation. The gradual channel expansion region is shown to manipulate cell equilibrium positions close to the microchannel walls, critical for higher efficiency collection. We demonstrate >80% removal of pathogenic bacteria from blood after two passes of the single channel system. The massively parallel device can process 240,mL/h with a throughput of 400 million cells/min. We expect that this parallelizable, robust, and label-free approach would be useful for filtration of blood as well as for other cell separation and concentration applications from large volume samples. Biotechnol. Bioeng. 2010;107: 302,311. © 2010 Wiley Periodicals, Inc. [source]