Unraveling Antimicrobial Resistance Genes and Phenotype Patterns among Enterococcus faecalis Isolated from Retail Chicken Products in Japan

Multidrug-resistant enterococci are considered crucial drivers for the dissemination of antimicrobial resistance determinants within and beyond a genus. These organisms may pass numerous resistance determinants to other harmful pathogens, whose multiple resistances would cause adverse consequences. Therefore, an understanding of the coexistence epidemiology of resistance genes is critical, but such information remains limited. In this study, our first objective was to determine the prevalence of principal resistance phenotypes and genes among Enterococcus faecalis isolated from retail chicken domestic products collected throughout Japan. Subsequent analysis of these data by using an additive Bayesian network (ABN) model revealed the co-appearance patterns of resistance genes and identified the associations between resistance genes and phenotypes. The common phenotypes observed among E. faecalis isolated from the domestic products were the resistances to oxytetracycline (58.4%), dihydrostreptomycin (50.4%), and erythromycin (37.2%), and the gene tet(L) was detected in 46.0% of the isolates. The ABN model identified statistically significant associations between tet(L) and erm(B), tet(L) and ant(6)-Ia, ant(6)-Ia and aph(3’)-IIIa, and aph(3’)-IIIa and erm(B), which indicated that a multiple-resistance profile of tetracycline, erythromycin, streptomycin, and kanamycin is systematic rather than random. Conversely, the presence of tet(O) was only negatively associated with that of erm(B) and tet(M), which suggested that in the presence of tet(O), the aforementioned multiple resistance is unlikely to be observed. Such heterogeneity in linkages among genes that confer the same phenotypic resistance highlights the importance of incorporating genetic information when investigating the risk factors for the spread of resistance. The epidemiological factors that underlie the persistence of systematic multiple-resistance patterns warrant further investigations with appropriate adjustments for ecological and bacteriological factors.     

Photo-movement of coral larvae influences vertical positioning in the ocean

Coral Reefs - Behaviour can have profound consequences for the dispersal potential of an organism. In the marine environment, larvae rely heavily on oceanic currents to migrate from one area to...     

Stabilization of ribose-5-phosphate isomerase from tobacco

The highly purified ribose phosphate isomerase from tobaccoleaves is heat labile. 0.2% of various kinds of proteins stabilizedisomerase activity when Mg⁺⁺ was present. 1x10^–3% polyethyleneglycol2,000 showed the same effect as the proteins did. Smaller polyediyleneglycolswere less effective. Polyhydroxyl compounds showed litde effect.Mn⁺⁺ or Sr⁺⁺ was also effective as a stabilizer instead of Mg⁺⁺. (Received March 8, 1976; )     

Age-Related Changes of Myelin Proteins in the Rat Peripheral Nervous System

Age-related changes in amounts of myelin proteins from rat sciatic nerve or spinal root were analyzed by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis (PAGE). In the aged peripheral nerve myelin, the relative amounts of band 105K and proteins X and Y increased, whereas those of proteins P0 and P1 and band 190K decreased. Band 105K purified by preparative SDS-PAGE exhibited three bands of 105K, 28K, and 21K at the second electrophoresis. A repeated SDS-PAGE did not improve the purity of bank 105K, but increased the ratio of 21K to 28K. Compared with P0 protein, band 105K has a very similar peptide map pattern and amino acid composition, as well as the identical NH2 terminal residue, isoleucine. These findings suggest that band 105K is an aggregate form of P0 protein and its fragment, 21K. The 21K protein is a distinct entity from X protein. The quantitative and qualitative alterations in myelin proteins, as we report here, may reflect continuing demyelination and remyelination in aged peripheral nerves.     

Effect of Glucose on the Interaction of Hydrophobic Compounds with the Alanine Receptor Field of Bacillus subtilis Spores during Initiation of Germination

Glucose interfered with the inhibitory action of hydrophobic compounds, such as n-octanol, diphenylamine and 2-tert-butylphenol, during L-alanine-initiated germination of Bacillus subtilis spores. The action of glucose on the action of the hydrophobic compounds was not competitive, and the binding affinity of glucose was not essentially affected by the hydrophobic compounds, indicating the presence of separate binding sites for glucose and the hydrophobic compounds. The binding affinity of D-alanine, a competitive inhibitor of L-alanine, was not affected by the hydrophobic compounds, indicating separate binding sites for D-alanine and the hydrophobic compounds. A possible arrangement of the binding sites for glucose and for the hydrophobic compounds in relation to those for L- and D-alanine on the spores is discussed.     

Distribution of Acid Proteinase Activity in Molluscs

Acid proteinases with an optimum around pH 3 were demontrated in various tissues of 12 molluscan species. Enzymes strongly inhibited by pepstatin were predominant and the molecular weights of those from two species were in the region of 38,000–68,000, suggesting that they were cathepsin D-type proteinases.     

New sesquiterpene lactone glucosides from the roots of Ferula varia

Five new eudesmane- (1–5), two new guaiane- (6 and 7) and one new germacrane-type (8) sesquiterpene lactone glucosides were isolated from the H₂O-soluble fraction of the roots of Ferula varia. Their structures were elucidated by extensive spectroscopic analyses. The absolute configuration of 1 was determined by modified Mosher's method.     

A noninvasive method for extracting bivalve DNA from the water-filled mantle cavity

Genetic studies play a great role for determining the biology of bivalves, particularly those covering population genetics, phylogeny, breeding, stock management, and conservation. However, DNA sampling methods that require removal of bivalves from the water and/or opening of their shells often cause stress and damage to bivalves, which can be lethal. The invasiveness of DNA sampling has made it difficult to conduct genetic studies in threatened species, rare species, and/or breeding lineages. In the present study, we developed a non-invasive method for bivalve DNA sampling using the water-filled mantle cavity (WMC). Our method can extract DNA from a small WMC sample (about 100 µl), collected using a fine needle and syringe without opening the shell. We demonstrated that the WMC sample contains intact mitochondrial and nuclear DNA. DNA contamination from other organisms, such as adjacent bivalve individuals, did not affect the resulting PCR and DNA sequencing analyses. Finally, the individuals from whom WMC was collected remained alive for more than 2 months after the experiments. This non-invasive method will be of great assistance in investigating the genetics of bivalves.