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.     

Regenerants from Ajuga hairy roots with high productivity of 20-hydroxyecdysone

Summary Regenerants derived from hairy roots of Ajuga reptans var. atropurpurea induced by infection with Agrobacterium rhizogenes MAFF03-01724 harboring pRi revealed a dwarfing response, i.e. decrease in leaf size, reduction in internode distance, and increase in leaf number. These morphogenic alterations were accompanied by an increase in root mass and lack of floral differentiation. In the pRi-transformed regenerants, the proportion of root mass to whole plant mass was higher than that of the untransformed ones, although both kinds of regenerants were comparable on a fresh weight basis. High capacity of rooting and 20-hydroxyecdysone production associated with the original hairy root line were stably maintained in clonal regenerants.     

Neurologic Abnormalities in Two Dogs Suspected Lyme Disease

A 2-year-old mongrel dog developed neurological signs following tick bite. These included astasia, persistent tonic convulsions and hyper-reflexia. Both serum IgG and IgM antibody titers against Borrelia burgdorferi were positive in enzyme-linked immunosorbent assay (ELISA). The neurological signs subsided after high-dose penicillin and streptomycin treatment. A strain of spirochetes (P427a) was isolated from the midgut of Ixodes persulcatus feeding on the dog. Morphological characteristic, immunological property and protein profile revealed that the isolate was B. burgdorferi. Similarly, a 2-year-old Labrador retriever dog developed neurological signs after tick bite and showed a positive IgG antibody titer against B. burgdorferi. Antibiotic treatment was effective also in this case. These findings suggest that neurological symptoms shown in both dogs were caused by infection with B. burgdorferi.     

Genetic Transformation in a Synchronous Culture of Streptococcus pneumoniae

Cultures of synchronized Streptococcus pneumoniae cells were prepared by amino acid starvation followed by refeeding, and the cellular reactivity towards the competence-activator for genetic transformation, i.e., competence induction on the addition of the activator, was investigated. Cyclical fluctuation in the level of competence was observed during the cell cycle. Especially, cells at division showed reduced cellular ability to develop competence. It was also observed that deprivation of nutritionally required amino acids had quite diiferent effects on the induction of competence, depending upon the amino acid removed: glutamine or serine starvation caused a significant reduction in the level of competence induced by the activator, whereas deprivation of other amino acids (histidine, leucine, isoleucine, valine, arginine and cysteine) did not.     

Synthesis of 6-Sulfur Analogues of Oxanosine and Closely Related Derivatives Thereof

Abstract

Novel β-D-ribofuranosides having a 5-substituted imidazo [4,5-d] [1,3]thiazine ring, including the S⁶-congener 3 of oxanosine 2, were synthesized for screening their anticancer and antiviral activities.     

cDNA of a Novel mRNA Expressed Predominantly in Mouse Kidney

We examined embryonic carcinoma (EC) cells for a potential prototype molecule of C3, the third component of complement. PCR primers, corresponding to the base sequence derived from the C3 cDNA of several species, were used for PCR amplification of the EC cell cDNA. All the PCR products obtained had the same sequence and showed no sequence homology to C3. Subsequently, cDNA clones were isolated from a mouse liver cDNA library using the PCR product as a probe. Unexpectedly, neither the base sequence of the cDNA clones nor the amino acid sequence deduced from the cDNA showed homology to C3, although partial homology was observed to a number of sequences from EST databases. We designated this new clone NCU-G1. Northern hybridization experiments revealed that NCU-G1 is expressed constitutively not only in the mouse fetus but also in various mouse tissues, and is most abundant in the kidney cortex.     

Introduction of amino acid residues at the N-terminus of the zeocin-resistance protein increases its expression in Saccharomyces cerevisiae

Nucleotide sequences proximal to the initiation codon of a gene are known to affect the expression efficiency of that gene. We screened 10-bp random sequences upstream of the initiation codon of the zeocin-resistance gene to identify sequences that could enhance its expression in Saccharomyces cerevisiae. Of the isolated sequences, 20 sequences exhibited a common feature, i.e. ATG at the position −9 through −7, which resulted in the incorporation of three amino acids at the N-terminus of the protein. The introduction of these sequences upstream of the initiation codon increased the expression levels of zeocin-resistance protein by 2.2–6.5-fold. One of these sequences increased the expression levels of three out of four human proteins, thereby suggesting that this sequence may also enhance the expression efficiency of mammalian proteins in yeast.     

Apterichtus keramanus, a new snake-eel from Okinawa, southern Japan (Ophichthinae, Ophichthidae)

A new snake-eel,Apterichtus keramanus, is described on the basis of a single 276-mm TL specimen trawled from the coast of Kerama Islands, Okinawa Prefecture, Japan. The species is unique in the genus in having the posterior nostril opening entirely inside the mouth and a dark band running from the anteroventral margin of the eye to the upper lip.