The Arabidopsis TAC Position Viewer: a high‐resolution map of transformation‐competent artificial chromosome (TAC) clones aligned with the Arabidopsis thaliana Columbia‐0 genome

We present a high‐resolution map of genomic transformation‐competent artificial chromosome (TAC) clones extending over all Arabidopsis thaliana (Arabidopsis) chromosomes. The Arabidopsis genomic TAC clones have been valuable genetic tools. Previously, we constructed an Arabidopsis genomic TAC library consisting of more than 10 000 TAC clones harboring large genomic DNA fragments extending over the whole Arabidopsis genome. Here, we determined 13 577 end sequences from 6987 Arabidopsis TAC clones and mapped 5937 TAC clones to precise locations, covering approximately 90% of the Arabidopsis chromosomes. We present the large‐scale data set of TAC clones with high‐resolution mapping information as a Java application tool, the Arabidopsis TAC Position Viewer, which provides ready‐to‐go transformable genomic DNA clones corresponding to certain loci on Arabidopsis chromosomes. The TAC clone resources will accelerate genomic DNA cloning, positional walking, complementation of mutants and DNA transformation for heterologous gene expression.     

Relationship Between the Quantity of Oral Candida and Systemic Condition/Diseases of the Host: Oral Candida Increases with Advancing Age and Anemia

Background

The impact of host systemic conditions/diseases on the prosperity of oral Candida colonies remains unclear. The aim of the present study was to investigate whether a relationship exists between the quantity of oral Candida and the systemic condition/diseases of the host.

Patients and Methods

The cross-sectional relationship between Candida mannan concentrations and health check-up results was analyzed in consideration of local conditions that influence the prevalence of oral Candida.

Results

Candida mannan concentrations correlated with age, the number of untreated decayed teeth, number of prosthetic teeth, salivary pH, HbA1c, and the red blood cell count in a univariate analysis. In a multivariate analysis, Candida mannan concentrations correlated with age, the number of untreated decayed teeth, number of prosthetic teeth, salivary pH, and the red blood cell count. Candida mannan concentrations were higher in subjects older than 80 years, with a higher number of either untreated or prosthetic teeth, with a lower salivary pH, and with a decreased red blood cell count. Mannan concentrations were slightly higher in subjects with elevated HbA1c.

Conclusions

The present results suggest a close relationship between the quantity of oral Candida and the systemic condition/diseases of the host. Oral Candida may increase in immunocompromised hosts.

     

Effects of Transcranial Direct Current Stimulation of the Posterior Parietal Cortex on the Control of Visual Attention

Neurophysiology - This study aimed at the effects of anodal transcranial direct current stimulation (tDCS) over the right posterior parietal cortex on the control of visual attention during walking...     

Magnetic fields generated by an induction heating (IH) cook top do not cause genotoxicity in vitro

The use of induction heater (IH) cook tops in homes has become widespread, especially in Japan, but there are concerns about the safety of intermediate frequency (IF) electromagnetic fields associated with these cooking appliances. Since the cellular genotoxicity of IF magnetic fields has not been examined in cultured cells, we examined the effects of these fields at a magnetic flux density of 532 +/- 20 microT at 23 kHz, using an exposure unit with a built-in CO2 incubator. Exposure to the IF magnetic field at 532 microT for 2 h did not affect the growth of CHO-K1 cells and caused no mutagenic effects in bacterial mutation assays. Exposure to the IF magnetic field for 2 h induced neither single nor double DNA strand breaks in comet assays, and caused no significant change in the mutation frequency at the HPRT locus compared to sham exposure. The magnetic field used in this study is more than 80 times higher than the level recommended as safe in the International Commission on Non-ionizing Radiation Protection (ICNIRP) guidelines. From these results, we suggest that exposure to an IF magnetic field for 2 h does not cause cellular genotoxicity in bacteria and in Chinese hamster cells. However, the possibility of effects on other cellular functions remains, and further studies on the cellular effects of IF magnetic fields are required.     

Altering cAMP levels within a central pattern generator modifies or disrupts rhythmic motor output

Cyclic AMP is a second messenger that has been implicated in the neuromodulation of rhythmically active motor patterns. Here, we tested whether manipulating cAMP affects swim motor pattern generation in the mollusc, Tritonia diomedea. Inhibiting adenylyl cyclase (AC) with 9-cyclopentyladenine (9-CPA) slowed or stopped the swim motor pattern. Inhibiting phosphodiesterase with 3-isobutyl-1-methylxanthine (IBMX) or applying dibutyryl-cAMP (dB-cAMP) disrupted the swim motor pattern, as did iontophoresing cAMP into the central pattern generator neuron C2. Additionally, during wash-in, IBMX sometimes temporarily produced extended or spontaneous swim motor patterns. Photolysis of caged cAMP in C2 after initiation of the swim motor pattern inhibited subsequent bursting. These results suggest that cAMP levels can dynamically modulate swim motor pattern generation, possibly shaping the output of the central pattern generator on a cycle-by-cycle basis.     

2-Hydroxyisoflavanone dehydratase is a critical determinant of isoflavone productivity in hairy root cultures of Lotus japonicus

Hairy root cultures of a model legume, Lotus japonicus, were established to characterize two heterologous cDNAs encoding enzymes involved in isoflavone biosynthesis, i.e. licorice 2-hydroxyisoflavanone synthase (IFS) and soybean 2-hydroxyisoflavanone dehydratase (HID) catalyzing sequential reactions to yield isoflavones. While the control and the IFS overexpressor did not accumulate detectable isoflavones, the HID overexpressors did accumulate daidzein and genistein, showing that HID is a critical determinant of isoflavone productivity. Production of coumestrol in all the genotypes and isoliquiritigenin/liquiritigenin in IFS + HID-overexpressing lines was also noted. These results provide insight into the regulatory mechanism that controls isoflavonoid biosynthesis.     

Regulation of Mammalian Cone Phototransduction by Recoverin and Rhodopsin Kinase

Cone photoreceptors function under daylight conditions and are essential for color perception and vision with high temporal and spatial resolution. A remarkable feature of cones is that, unlike rods, they remain responsive in bright light. In rods, light triggers a decline in intracellular calcium, which exerts a well studied negative feedback on phototransduction that includes calcium-dependent inhibition of rhodopsin kinase (GRK1) by recoverin. Rods and cones share the same isoforms of recoverin and GRK1, and photoactivation also triggers a calcium decline in cones. However, the molecular mechanisms by which calcium exerts negative feedback on cone phototransduction through recoverin and GRK1 are not well understood. Here, we examined this question using mice expressing various levels of GRK1 or lacking recoverin. We show that although GRK1 is required for the timely inactivation of mouse cone photoresponse, gradually increasing its expression progressively delays the cone response recovery. This surprising result is in contrast with the known effect of increasing GRK1 expression in rods. Notably, the kinetics of cone responses converge and become independent of GRK1 levels for flashes activating more than ∼1% of cone pigment. Thus, mouse cone response recovery in bright light is independent of pigment phosphorylation and likely reflects the spontaneous decay of photoactivated visual pigment. We also find that recoverin potentiates the sensitivity of cones in dim light conditions but does not contribute to their capacity to function in bright light.