Direct acid-catalysed transmethylation of lactobacillic acid in lactic acid bacteria

Summary Cellular fatty acids inLactobacillus büchneri were transmethylated with H₂SO₄ catalyst in methanol at elevated temperature. By optimising the reaction time and the amounts of catalyst and methanol used at a fixed temperature it was possible to maximise the lactobacillic acid yield. The yield of lactobacillic acid with this method was better than with the traditional method using base-catalysed saponification followed by HCL-catalysed methylation.     

Determination of cis,cis-methylene interrupted polyunsaturated fatty acids in aqueous solutions by lipoxygenase chemiluminescence

The chemiluminescent reaction of luminol during lipoxygenase-catalyzed oxygenations was studied with the purpose of developing a specific luminometric assay for cis,cis-1,4-pentadiene fatty acids directly in aqueous solutions. The addition of picomole levels of either linoleic or arachidonic acids to reaction systems containing 0.04 mM luminol and 40 micrograms/ml of purified soybean lipoxygenase-1 gave light emission curves with a single sharp maximum. Under these conditions the peak heights were linearly dependent on the fatty acid concentration and the detection limit for both of the fatty acids was 2 pmol with a signal to noise ratio of 2. For maximum reproducibility of the assays a procedure for the proper quantitation of the enzyme was developed. The fact that the assay proved to be relatively interference-free was ascribed to the high molar enzyme/substrate ratio (above 1).     

Changes in fatty acid branching and unsaturation of Streptomyces griseus and Brevibacterium fermentans as a response to growth temperature.

Streptomyces griseus showed three different modes of changing fatty acids in response to temperature change. In Brevibacterium fermentans, two such responses were found. The responses involved changes in fatty acid branching, unsaturation, or chain length, depending on growth temperature range. Changes in unsaturation of branched-chain acids were characteristic at low growth temperatures.     

Metabolic epidemiology of large bowel cancer. Fecal mutagens in high- and low-risk population for colon cancer. A preliminary report

Because of potential significance of fecal mutagens in the pathogenesis of colon cancer, the dietary pattern and fecal mutagens of 3 populations with distinct risk for the development of colon cancer, a high-risk population in New York Metropolitan area (non-Seventh-Day Adventists), a low-risk population of vegetarian Seventh-Day Adventists in New York Metropolitan area and a low-risk population in rural Kuopio, Finland were studied. The average daily intake of protein was the same in the 3 groups, but the sources were different, a greater portion coming from meat in the New York non-Seventh-Day Adventists and from vegetables in Seventh-Day Adventists. The intake of fat was lower in Seventh-Day Adventists and higher in Kuopio and in New York non-Seventh-Day Adventists. The intake of dietary fiber was high in Kuopio compared to other groups. Fecal samples collected for 2 days were freeze-dried extracted with peroxide-free diethyl ether, partially purified on a silica-gel column and assayed for mutagenicity using the Salmonella/mammalian microsome mutagenicity test. The mutagenic activity was observed with Salmonella typhimurium tester strain TA98 without microsomal activation and with TA100 with and without microsomal activation in high-risk subjects from New York consuming a high-fat, high-meat diet. The incidence of fecal mutagen activity was higher in volunteers from New York consuming a high-fat, high-meat diet compared to low-risk rural Kuopio population. None of the vegetarian Seventh-Day Adventists showed any mutagenic activity.     

Decreased muscarinic receptor binding in cerebral cortex and hippocampus in Alzheimer's disease

Muscarinic (cholinergic) receptor binding sites (MRB) were studied by determining the 3H-QNB binding in four cortical areas and hippocampus of 20 histologically confirmed Alzheimer patients and comparing these with corresponding controls. Alzheimer patients dying at younger age (less than or equal to 80) with profound decrease in choline-acetyltransferase activity (by 61-85%) and without any, possibly MRB modifying, drug treatment showed 30% decrease in MRB in the frontal cortex (p less than 0.05), 28% in the temporal cortex (p less than 0.05) and 37% in the hippocampus (p less than 0.01). These findings further suggest that muscarinic receptors are affected in Alzheimer's disease, at least in advanced state of the disease.     

Acrylic microspheres in vivo. X. Elimination of circulating cells by active targeting using specific monoclonal antibodies bound to microparticles

The elimination from the blood of 51Cr-labelled mouse erythrocytes modified with trinitrophenyl (TNP) groups was followed in mice. After 24 hours, when a stable concentration of the labelled erythrocytes has been attained, monoclonal anti-TNP-antibodies were given intravenously, either in free, soluble form, or bound to microparticles containing immobilized protein A. The anti-TNP-antibodies induced a rapid elimination of the TNP- and 51Cr-labelled erythrocytes. Over the 8-hours time period studied, the elimination rate was significantly faster when the antibodies were administered bound to the particles. After the elimination of the target cells, the radioactivity was found in the liver, spleen and bone marrow. These results and relevant control experiments indicate that a solid carrier 1. can be directed to a specific target cell with a specific antibody and 2. can induce a rapid elimination of the target cell from the circulation.     

Rapid identification of bacterial pathogens using a PCR- and microarray-based assay

Background  

During the course of a bacterial infection, the rapid identification of the causative agent(s) is necessary for the determination of effective treatment options. We have developed a method based on a modified broad-range PCR and an oligonucleotide microarray for the simultaneous detection and identification of 12 bacterial pathogens at the species level. The broad-range PCR primer mixture was designed using conserved regions of the bacterial topoisomerase genes gyrB and parE. The primer design allowed the use of a novel DNA amplification method, which produced labeled, single-stranded DNA suitable for microarray hybridization. The probes on the microarray were designed from the alignments of species- or genus-specific variable regions of the gyrB and parE genes flanked by the primers. We included mecA-specific primers and probes in the same assay to indicate the presence of methicillin resistance in the bacterial species. The feasibility of this assay in routine diagnostic testing was evaluated using 146 blood culture positive and 40 blood culture negative samples.     

Loss of Competition in the Outside Host Environment Generates Outbreaks of Environmental Opportunist Pathogens

Environmentally transmitted pathogens face ecological interactions (e.g., competition, predation, parasitism) in the outside-host environment and host immune system during infection. Despite the ubiquitousness of environmental opportunist pathogens, traditional epidemiology focuses on obligatory pathogens incapable of environmental growth. Here we ask how competitive interactions in the outside-host environment affect the dynamics of an opportunist pathogen. We present a model coupling the classical SI and Lotka–Volterra competition models. In this model we compare a linear infectivity response and a sigmoidal infectivity response. An important assumption is that pathogen virulence is traded off with competitive ability in the environment. Removing this trade-off easily results in host extinction. The sigmoidal response is associated with catastrophic appearances of disease outbreaks when outside-host species richness, or overall competition pressure, decreases. This indicates that alleviating outside-host competition with antibacterial substances that also target the competitors can have unexpected outcomes by providing benefits for opportunist pathogens. These findings may help in developing alternative ways of controlling environmental opportunist pathogens.