In Vivo Bioluminescence Analyses of Circadian Rhythms in Arabidopsis thaliana Using a Microplate Luminometer.

Our understanding of the circadian clock function in plants has been markedly assisted by studies with the model species Arabidopsis thaliana. Molecular and genetics approaches have delivered a comprehensive view of the transcriptional regulatory networks underlying the Arabidopsis circadian system. The use of the luciferase as a reporter allowed the precise in vivo determination of circadian periods, phases, and amplitudes of clock promoter activities with unprecedented temporal resolution. An increasing repertoire of fine-tuned luciferases together with additional applications such as translational fusions or bioluminescence molecular complementation assays have considerably expanded our view of circadian protein expression and activity, far beyond transcriptional regulation. Further applications have focused on the in vivo simultaneous examination of rhythms in different parts of the plant. The use of intact versus excised plant organs has also provided a glimpse on both the organ-specific and autonomy of the clocks and the importance of long distance communication for circadian function. This chapter provides a basic protocol for in vivo high-throughput monitoring of circadian rhythms in Arabidopsis seedlings using bioluminescent reporters and a microplate luminometer.

Circadian autonomy and rhythmic precision of the Arabidopsis female reproductive organ.

The plant circadian clock regulates essential biological processes including flowering time or petal movement. However, little is known about how the clock functions in flowers. Here, we identified the circadian components and transcriptional networks contributing to the generation of rhythms in pistils, the female reproductive organ. When detached from the rest of the flower, pistils sustain highly precise rhythms, indicating organ-specific circadian autonomy. Analyses of clock mutants and chromatin immunoprecipitation assays showed distinct expression patterns and specific regulatory functions for clock activators and repressors in pistils. Genetic interaction studies also suggested a hierarchy of the repressing activities that provide robustness and precision to the pistil clock. Globally, the circadian function in pistils primarily governs responses to environmental stimuli and photosynthesis and controls pistil growth and seed weight and production. Understanding the circadian intricacies in reproductive organs may prove useful for optimizing plant reproduction and productivity.

Circadian Control of Metabolism by the Clock Component TOC1.

Photosynthesis in chloroplasts during the day and mitochondrial respiration during the night execute nearly opposing reactions that are coordinated with the internal cellular status and the external conditions. Here, we describe a mechanism by which the Arabidopsis clock component TIMING OF CAB EXPRESSION1 (TOC1) contributes to the diurnal regulation of metabolism. Proper expression of TOC1 is important for sustaining cellular energy and for the diel and circadian oscillations of sugars, amino acids and tricarboxylic acid (TCA) cycle intermediates. TOC1 binds to the promoter of the TCA-related gene FUMARASE 2 to repress its expression at night, which results in decreased fumarate accumulation in TOC1 over-expressing plants and increased in toc1-2 mutant. Genetic interaction studies confirmed that over-expression of FUMARASE 2 in TOC1 over-expressing plants alleviates the molecular and physiological energy-deprivation phenotypes of TOC1 over-expressing plants. Thus, we propose that the tandem TOC1-FUMARASE 2 is one of the mechanisms that contribute to the regulation of plant metabolism during the day and night.

Monitoring single-cell bioluminescence of Arabidopsis leaves to quantitatively evaluate the efficiency of a transiently introduced CRISPR/Cas9 system targeting the circadian clock gene ELF3.

The rapid assessment of gene function is crucial in biological research. The CRISPR/Cas9 system is widely used as a tool for targeted gene editing in many organisms including plants. Previously, we established a transient gene expression system for investigating cellular circadian rhythms in duckweed. In this system, circadian reporters and clock gene effectors-such as overexpressors, RNA interference (RNAi), and CRISPR/Cas9-were introduced into duckweed cells using a particle bombardment method. In the present study, we applied the CRISPR/Cas9 system at a single cell level to Arabidopsis thaliana, a model organism in plant biology. To evaluate the mutation induction efficiency of the system, we monitored single-cell bioluminescence after application of the CRISPR/Cas9 system targeting the ELF3 gene, which is essential for robust circadian rhythmicity. We evaluated the mutation induction efficiency by determining the proportion of cells with impaired circadian rhythms. Three single guide RNAs (sgRNAs) were designed, and the proportion of arrhythmic cells following their use ranged from 32 to 91%. A comparison of the mutation induction efficiencies of diploid and tetraploid Arabidopsis suggested that endoreduplication had a slight effect on efficiency. Taken together, our results demonstrate that the transiently introduced CRISPR/Cas9 system is useful for rapidly assessing the physiological function of target genes in Arabidopsis cells.

Factors related to independent social living of poststroke patients with mild impairment.

PURPOSE: To evaluate factors related to independent social living of poststroke patients with mild impairment who live at home after hospitalization. PARTICIPANTS: Forty-one participants were selected who scored 80 points or more on the Barthel Index (BI) and 25 or more points on the revised Hasegawa Dementia Scale (HDS-R). All of them returned home after receiving functional exercises for poststroke rehabilitation. METHOD: The functional data of inpatients and the results of a mailed questionnaire based on the Tokyo Metropolitan Institute of Gerontology (TMIG) index and the Craig Handicap Assessment and Reporting Technique, revised Japanese version (CHART-J), were compared. RESULTS: Of the 6 CHART dimensions, Social Integration and Economic Self-sufficiency did not correlate with functional data during the hospitalized period. Participants generally scored lower in Occupation than in the other CHART dimensions with a higher standard deviation. CONCLUSION: From the viewpoint of functional impairment of poststroke patients, their motor function can be estimated relatively easily, but such dimensions as Social Integration and Economic Self-sufficiency are more difficult to evaluate with other methods. CHART is useful for evaluating the social activity of poststroke patients who live at home.

Synchrony of plant cellular circadian clocks with heterogeneous properties under light/dark cycles.

Individual cells in a plant can work independently as circadian clocks, and their properties are the basis of various circadian phenomena. The behaviour of individual cellular clocks in Lemna gibba was orderly under 24-h light/dark cycles despite their heterogeneous free-running periods (FRPs). Here, we reveal the entrainment habits of heterogeneous cellular clocks using non-24-h light/dark cycles (T-cycles). The cellular rhythms of AtCCA1::LUC under T = 16 h cycles showed heterogeneous entrainment that was associated with their heterogeneous FRPs. Under T = 12 h cycles, most cells showed rhythms having ~24-h periods. This suggested that the lower limit of entrainment to the light/dark cycles of heterogeneous cellular circadian clocks is set to a period longer than 12 h, which enables them to be synchronous under ~24-h daily cycles without being perturbed by short light/dark cycles. The entrainment habits of individual cellular clocks are likely to be the basis of the circadian behaviour of plant under the natural day-night cycle with noisy environmental fluctuations. We further suggest that modifications of EARLY FLOWERING3 (ELF3) in individual cells deviate the entrainability to shorter T-cycles possibly by altering both the FRPs and light responsiveness.

Cardiorespiratory fitness of post-stroke patients: as inpatients and as outpatients.

The objective of this study was to determine the relationship between disuse weakness due to acute or subacute stroke and cardiorespiratory fitness. The participants were 15 men (average age 48.4 years) who were acute admissions to a hospital specializing in the management of stroke, 11 with cerebral infarction and four with intracerebral hemorrhage. All participants received physiotherapy (40 min/day, 5 days/week) at their bedside until leaving hospital. None of them received physiotherapy in an outpatient clinic. The anaerobic threshold (AT) was measured twice: during admission (an average of 37.3 days after onset) and after discharge (in an outpatient clinic, an average of 37 days after discharge and 42.7 days after the first test). The average AT was 12.5 ml/kg/min in the first test and 14.2 ml/kg/min in the second test (P<0.05). Because ATs in patients were lower after discharge than for healthy control individuals, physiotherapy during admission for stroke should be qualitatively and quantitatively reexamined for the prevention of disuse weakness. After discharge, it is important to give patients a more active rehabilitation program to improve their fitness.

[Neurobehavioral toxicity of acrylamide and IDPN (3,3'-iminodipropionitrile) in rats by 28-day oral administration--problems encountered in collaborative study and a commentary on conducting neurobehavioral testing].

In order to clarify technical problems in evaluating neurotoxicity of chemicals and to solve them, a collaborative study with a common protocol was conducted at 11 domestic safety research laboratories. In the collaborative study, acrylamide and IDPN (3,3'-iminodipropionitrile), which are known neurotoxicants, were used, and the chemicals were orally administered to rats for 28 days. In addition to the clinical observation done routinely, detailed clinical observation, sensory and motor function tests including grip strength and motor activity were performed to evaluate neurobehavioral toxicity with reference to Functional Observational Battery (FOB). In general, neurobehavioral toxicity of the two chemicals was detected in the collaborative study. However, we also encountered technical problems, since neurobehavioral testing was unfamiliar to us. In the present report, we describe the major problems and how to solve them, and briefly explain the neurobehavioral testing procedure.

Repetitive stepwise rotaxane formation toward programmable molecular arrays.

We present a novel strategy to synthesize multi-molecular arrays in a programmable way by stepwise elongation based on repetition of two-fold rotaxane formation and construction of threads. A cofacially triply stacked porphyrin array was obtained via the repetitive two-fold rotaxane formation.

In vivo imaging and quantitative monitoring of autophagic flux in tobacco BY-2 cells.

Autophagy has been shown to play essential roles in the growth, development and survival of eukaryotic cells. However, simple methods for quantification and visualization of autophagic flux remain to be developed in living plant cells. Here, we analyzed the autophagic flux in transgenic tobacco BY-2 cell lines expressing fluorescence-tagged NtATG8a as a marker for autophagosome formation. Under sucrose-starved conditions, the number of punctate signals of YFP-NtATG8a increased, and the fluorescence intensity of the cytoplasm and nucleoplasm decreased. Conversely, these changes were not observed in BY-2 cells expressing a C-terminal glycine deletion mutant of the NtATG8a protein (NtATG8aΔG). To monitor the autophagic flux more easily, we generated a transgenic BY-2 cell line expressing NtATG8a fused to a pH-sensitive fluorescent tag, a tandem fusion of the acid-insensitive RFP and the acid-sensitive YFP. In sucrose-rich conditions, both fluorescent signals were detected in the cytoplasm and only weakly in the vacuole. In contrast, under sucrose-starved conditions, the fluorescence intensity of the cytoplasm decreased, and the RFP signal clearly increased in the vacuole, corresponding to the fusion of the autophagosome to the vacuole and translocation of ATG8 from the cytoplasm to the vacuole. Moreover, we introduce a novel simple easy way to monitor the autophagic flux non-invasively by only measuring the ratio of fluorescence of RFP and YFP in the cell suspension using a fluorescent image analyzer without microscopy. The present in vivo quantitative monitoring system for the autophagic flux offers a powerful tool for determining the physiological functions and molecular mechanisms of plant autophagy induced by environmental stimuli.

Stimulation of butyrate production by gluconic acid in batch culture of pig cecal digesta and identification of butyrate-producing bacteria.

Gluconic acid reaches the large intestine to stimulate lactic acid bacteria. However, the fermentation pattern of gluconic acid has yet to be elucidated. Accordingly, we examined the fermentation properties induced by gluconic acid in the pig cecal digesta in vitro. We also tested sorbitol and glucose, substrates for which the fermentation rate and patterns are known. The gluconic acid-utilizing bacteria were further isolated from pig cecal digesta and identified to examine the effect of gluconic acid on hind gut fermentation. Gluconic acid was fermented more slowly than were the other two substrates. Gluconic acid stimulated butyrate production; the butyrate molar percentage reached 26%, which is considered a high butyrate production. The majority of gluconic acid fermenters were identified as lactic acid bacteria, such as Lactobacillus reuteri and L. mucosae, and acid-utilizing bacteria, such as Megasphaera elsdenii and Mitsuokella multiacida. The gluconic acid fermented by lactic acid bacteria, and the lactate and acetate that were produced were used to form butyrate by acid-utilizing bacteria, such as M. elsdenii. Gluconic acid may be useful as a prebiotic to stimulate butyrate production in the large intestine.

Development of a new chemically defined sporulation medium for the yeasts in the genus Lipomyces.

A chemically defined sporulation medium (AF medium) for the yeasts belonging to the genus Lipomyces was developed. The chemical composition was derived from chemical analyses of soybean extract. Some chemical modification of the AF medium indicated that the nitrogen sources (aspartic and glutamic acids) and zinc ion were essential for sporulation. The significance of medium pH was discussed.