Comparison of Chemical Sensitivity of Fresh and Long-Stored Heat Resistant Neosartorya fischeri Environmental Isolates Using BIOLOG Phenotype MicroArray System

Spoilage of heat processed food and beverage by heat resistant fungi (HRF) is a major problem for food industry in many countries. Neosartorya fischeri is the leading source of spoilage in thermally processed products. Its resistance to heat processing and toxigenicity makes studies about Neosartorya fischeri metabolism and chemical sensitivity essential. In this study chemical sensitivity of two environmental Neosartorya fischeri isolates were compared. One was isolated from canned apples in 1923 (DSM3700), the other from thermal processed strawberry product in 2012 ({"type":"entrez-nucleotide","attrs":{"text":"KC179765","term_id":"452916796"}}KC179765), used as long-stored and fresh isolate, respectively. The study was conducted using Biolog Phenotype MicroArray platforms of chemical sensitivity panel and traditional hole-plate method. The study allowed for obtaining data about Neosartorya fischeri growth inhibitors. The fresh isolate appeared to be much more resistant to chemical agents than the long-stored isolate. Based on phenotype microarray assay nitrogen compounds, toxic cations and membrane function compounds were the most effective in growth inhibition of N. fischeri isolates. According to the study zaragozic acid A, thallium(I) acetate and sodium selenate were potent and promising N. fischeri oriented fungicides which was confirmed by both chemical sensitivity microplates panel and traditional hole-plate methods.     

HAEMOPOIETIC STEM CELL (CFU) KINETICS IN THE CULTURE

Haemopoiesis continued for over 2 months in organ culture of embryonal mouse liver, and haemopoietic stem cells (CFU_s) capable of DNA-synthesis were found in it all that time. Between the 10th and 40th day the number of stem cells in the culture was sustained in a steady state. Both in normal and in regenerating adult bone marrow haemopoiesis ceased within a short time in the culture. Induction of proliferation in haemopoietic stem cells combined with undamaged or improved micro-environment resulted in a little better maintenance of CFU_s in the adult bone marrow culture, The results are discussed in the light of current concepts of haemopoietic stem cell regulation.     

Stalked Bacteria: Properties of Deoxriybonucleic Acid Bacteriophage φCbK

The Caulobacter crescentus bacteriophage phiCbK was studied with respect to the physical and chemical properties of both the phage and its deoxyribonucleic acid (DNA). Electron micrographs reveal the phage to be among the largest DNA bacteriophages reported, with head dimensions of 64 by 195 nm and a flexible tail 275 nm in length. The phage is composed of 57% DNA. This DNA is double-stranded as indicated by (i) the sharp increase in extinction coefficient over a narrow range of temperature increase, (ii) an increase in density in CsCl upon thermal denaturation, and (iii) the equivalence of guanine and cytosine as well as adenine and thymine, determined by chemical analysis. phiCbK DNA cosediments with Escherichia coli phage T2 DNA and has therefore been assigned an S(20,w) value of 63.5S. The size of the phage and its DNA and the percentage of DNA indicate that the phiCbK phage head is relatively loosely packed. The properties of the DNA from bacteriophage phiCbK are similar to those of host C. crescentus DNA with respect to buoyant density, thermal transition point, and guanine plus cytosine content.     

Lack of protection against ascending Escherichia coli pyelonephritis in diabetic rats following immunization with purified lipopolysaccharide

Purified lipopolysaccharide of Escherichia coli produced specific antibody when injected intraperitoneally or given to rats orally. Either route of immunization did not prevent ascending pyelonephritis in a diabetic rat model. The use of purified LPS excludes the potential contribution of other virulence factors of E. coli as protective antigens in the prevention of ascending pyelonephritis and confirms that anti-lipopolysaccharide antibody is not protective for ascending pyelonephritis.     

Reductions of Γ-Aminobutyric Acid and Glutamate Uptake and (Na++ K+)-ATPase Activity in Brain Slices and Synaptosomes by Arachidonic Acid

Arachidonic acid, a major polyunsaturated fatty acid of membrane phospholipids in the CNS, reduced the high-affinity uptake of glutamate and gamma-aminobutyric acid (GABA) in both rat brain cortical slices and synaptosomes. alpha-Aminoisobutyric acid uptake was not affected. Intrasynaptosomal sodium was increased concomitant with decreased (Na+ + K+)-ATPase activity in synaptosomal membranes. The reduction of GABA uptake in synaptosomes could be partially reversed by alpha-tocopherol. The inhibition of membrane-bound (Na+ + K+)-ATPase by arachidonic acid was not due to a simple detergent-like action on membranes, since sodium dodecyl sulfate stimulated the sodium pump activity in synaptosomes. These data indicate that arachidonic acid selectively modifies membrane stability and integrity associated with reductions of GABA and glutamate uptake and of (Na+ + K+)-ATPase activity.     

Dimensions of the ion channel in neuronal nicotinic acetylcholine receptor as estimated from analysis of conformation-activity relationships of open-channel blocking drugs

Summary Relationship between the size of the molecule in the series of organic ions Et₃N–(CH₂)₅–N⁺R¹R²R³ (R ⁱ -alkyl or cycloalkyl substituents) and their abilities to block nicotinic acetylcholine receptors (AChRs) due to their open-channel blockade in the neurons of autonomic ganglia and in frog end-plate was analyzed.All low-energy equilibrium conformations of the drugs were calculated by the molecular mechanics method. A unique rectangular channel profile 6.1×8.3 Å. for which the best correlation between blocking activity of the drugs and total population of their conformations being able to penetrate into the channel, was deduced from all those tested.     

Effect of caffeine and glycerin on the Ca transport system of sarcoplasmic reticulum fragments from frog skeletal muscles

Parameters of the Ca2+-ion transport system by a fragmented sarcoplasmic reticulum isolated from phasic and tonic frog skeletal muscles were investigated under the action of caffeine or caffeine in combination with glycerol. No changes were observed in the Ca-transport system of a light fraction of the sarcoplasmic reticulum under the influence of caffeine and caffeine-glycerol combination. Caffeine reduced the value of Ca/ATP and enhanced the outflux of Ca2+-ions from membrane fragments of the caffeine-sensitive sarcoplasmic reticulum fraction of both the muscles; the combined effect of caffeine and glycerol was analogous to the action of caffeine applied alone. It is concluded that the potentiation of muscle contraction in the presence of glycerol is not due to the excess of Ca-release from the sarcoplasmic reticulum caused by this agent.     

Neural factors that stimulate ecdysteroid synthesis by the larval ring gland ofDrosophila melanogaster

Summary The larval ring gland ofDrosophila melanogaster is the source of ecdysteroids responsible for larval-larval and larval-pupal molting. An extract prepared from theDrosophila larval central nervous system, that presumably contains prothoracicotropic hormone, elicits a significant and dose-dependent in vitro increase in ecdysteroid synthesis by ring glands from wandering third instar larvae. The synthesis of all three ecdysteroids previously identified as ring gland products is elevated by more than two-fold in the presence of neural extract. The maximum response occurs within 30 min and can be sustained for at least two hours after a 30 min exposure to neural extract. No non-neural tissue extracts evoke a response and most of the prothoracicotropic activity originates in the ventral ganglion. However, while extract prepared from larval brains elicits only a slight increase in ecdysteroid synthesis, it enhances the activity of a submaximal dose of ventral ganglion extract. This suggests that two or more neural factors, at least one from the brain lobes and another from the ventral ganglion, interact to stimulate ecdysteroid synthesis by the larval ring gland.Abbreviations CNS central nervous system - HPLC high performance liquid chromatography - PTTH prothoracicotropic hormone - RIA radioimmunoassay