Effect of various substances on cultured mammalian cell growth

The effect of different home industry materials on the growth of Chinese hamster cells in culture has been studied. The plating efficiency of the culture and the ability to produce a monolayer were used as criteria. The materials under study can be divided into three groups: indifferent materials, those partially inhibiting the cell growth, and destructive ones. While constructing the apparatus for cultivation, the following materials are to chosen: titanium, molybdenum glass, plexiglass, polycarbonate, lavsan, polyethylene, fruorine films, pentoplast, silicon rubber, stainless steel, white food plate rubber, teflon, polymerized epoxy resin.     

Evaluation of the Phylogenetic Diversity of Prokaryotic Microorganisms in Sphagnum Peat Bogs by Means of Fluorescence In Situ Hybridization (FISH)

The microbial population of sphagnum peat bogs of northern Russia was analyzed with respect to the presence and cell numbers of representatives of particular phylogenetic groups of prokaryotes by means of in situ hybridization with fluorescently labeled group-specific rRNA-targeted oligonucleotide probes with broad detection spectra. The total number of cells that hybridized with universal Archaea- and Bacteria-specific probes varied, in peat samples of different bogs, from 45 to 83% of the number of cells revealed by DAPI staining. Down the bog profiles, the total number of prokaryotes and the fraction of archaea among them increased. Application of a set of oligonucleotide probes showed that the number of microorganisms belonging to such phylogenetic lineages of the domain Bacteria as the phyla Proteobacteria, Bacteroidetes, Actinobacteria, Firmicutes, Acidobacteria, and Planctomycetes constituted, in total, 14.0–26.5% of the number of eubacteria detected in the samples. Among the bacteria identified in the peat samples, the most abundant were representatives of the classes Alphaproteobacteria and Betaproteobacteria and the phyla Acidobacteria, Bacteroidetes, and Actinobacteria.     

Noncontact dipole effects on channel permeation. III. Anomalous proton conductance effects in gramicidin

Proton transport on water wires, of interest for many problems in membrane biology, is analyzed in side-chain analogs of gramicidin A channels. In symmetrical 0.1 N HCl solutions, fluorination of channel Trp(11), Trp-(13), or Trp(15) side chains is found to inhibit proton transport, and replacement of one or more Trps with Phe enhances proton transport, the opposite of the effects on K(+) transport in lecithin bilayers. The current-voltage relations are superlinear, indicating that some membrane field-dependent process is rate limiting. The interfacial dipole effects are usually assumed to affect the rate of cation translocation across the channel. For proton conductance, however, water reorientation after proton translocation is anticipated to be rate limiting. We propose that the findings reported here are most readily interpreted as the result of dipole-dipole interactions between channel waters and polar side chains or lipid headgroups. In particular, if reorientation of the water column begins with the water nearest the channel exit, this hypothesis explains the negative impact of fluorination and the positive impact of headgroup dipole on proton conductance.     

Continuous cultivation of hybridoma cells in cell reactor

Summary Mouse hybridoma cells were grown on surface of glass disks in a cell reactor. It is shown that during continuous cultivation the cells retain their antibody-producing ability. The yield of the culture supernatant obtained in the reactor exceeds about 5 fold those obtained in flasks with equivalent area.     

Formation and Properties of Persister Cells of Staphylococcus capitis and Staphylococcus epidermidis,Bacteria Inhabiting Human Skin

Microbiology - Persisters (P) are the cells surviving, but not reproducing in the presence of lethal doses of antibiotics (AB). These are the cells of a scarce (0.001–1.0%) subpopulation,...