A CCR4-associated factor 1, OsCAF1B, confers tolerance of low-temperature stress to rice seedlings.

KEY MESSAGE: Rice is an important crop in the world. However, little is known about rice mRNA deadenylation, which is an important regulation step of gene expression at the post-transcriptional level. The CCR4-NOT1 complex contains two key components, CCR4 and CAF1, which are the main cytoplasmic deadenylases in eukaryotic cells. Expression of OsCAF1B was tightly coupled with low-temperature exposure. In the present study, we investigated the function of OsCAF1B in rice by characterizing the molecular and physiological responses to cold stress in OsCAF1B overexpression lines and dominant-negative mutant lines. Our results demonstrate that OsCAF1B plays an important role in growth and development of rice seedlings at low temperatures. Rice is a tropical and subtropical crop that is sensitive to low temperature, and activates a complex gene regulatory network in response to cold stress. Poly(A) tail shortening, also termed deadenylation, is the rate-limiting step of mRNA degradation in eukaryotic cells. CCR4-associated factor 1 (CAF1) proteins are important enzymes for catalysis of mRNA deadenylation in eukaryotes. In the present study, the role of a rice cold-induced CAF1, OsCAF1B, in adaptation of rice plants to low-temperature stress was investigated. Expression of OsCAF1B was closely linked with low-temperature exposure. The increased survival percentage and reduced electrolyte leakage exhibited by OsCAF1B overexpression transgenic lines subjected to cold stress indicate that OsCAF1B plays a positive role in rice growth under low ambient temperature. The enhancement of cold tolerance by OsCAF1B in transgenic rice seedlings involved OsCAF1B deadenylase gene expression, and was associated with elevated expression of late-response cold-related transcription factor genes. In addition, the expression level of OsCAF1B was higher in a cold-tolerant japonica rice cultivar than in a cold-sensitive indica rice cultivar. The results reveal a hitherto undiscovered function of OsCAF1B deadenylase gene expression, which is required for adaptation to cold stress in rice.

A CCR4 Association Factor 1, OsCAF1B, Participates in the αAmy3 mRNA Poly(A) Tail Shortening and Plays a Role in Germination and Seedling Growth.

Poly(A) tail (PAT) shortening, also termed deadenylation, is the rate-limiting step of mRNA degradation in eukaryotic cells. The carbon catabolite repressor 4-associated factor 1s (CAF1s) were shown to be one of the major enzymes for catalyzing mRNA deadenylation in yeast and mammalian cells. However, the functions of CAF1 proteins in plants are poorly understood. Herein, a sugar-upregulated CAF1 gene, OsCAF1B, is investigated in rice. Using gain-of-function and dominant-negative mutation analysis, we show that overexpression of OsCAF1B resulted in an accelerated α-amylase gene (αAmy3) mRNA degradation phenomenon, while ectopic expression of a form of OsCAF1B that had lost its deadenylase activity resulted in a delayed αAmy3 mRNA degradation phenomenon in transgenic rice cells. The change in αAmy3 mRNA degradation in transgenic rice is associated with the altered lengths of the αAmy3 mRNA PAT, indicating that OsCAF1B acts as a negative regulator of αAmy3 mRNA stability in rice. Additionally, we found that overexpression of OsCAF1B retards seed germination and seedling growth. These findings indicate that OsCAF1B participates in sugar-induced αAmy3 mRNA degradation and deadenylation and acts a negative factor for germination and seedling development.

Novel interaction between CCR4 and CAF1 in rice CCR4-NOT deadenylase complex.

KEY MESSAGE: Rice is an important crop in the world. However, little is known about rice mRNA deadenylation, which is an important regulation step of gene expression at the post-transcriptional level. The CCR4-NOT1 complex contains two key components, CCR4 and CAF1, which are the main cytoplasmic deadenylases in eukaryotic cells. In yeast and humans, CCR4 can interact with CAF1 via its N-terminal LRR domain. However, no CCR4 protein containing N-terminal LRR motifs have been found in plants. In this manuscript, we demonstrate a novel pattern of interaction between OsCCR4 and OsCAF1 in the rice CCR4-NOT complex, and that OsCAF1 acts as a bridge between OsCCR4 and OsNOT1 in this complex. Our results revealed that the Mynd-like domain at the N-terminus of rice CCR4 proteins and the PXLXP motif at the rice CAF1 N-terminus play critical roles in OsCCR4-OsCAF1 interaction. Deadenylation, also called poly(A) tail shortening, is the first rate-limiting step in general cytoplasmic mRNA degradation in eukaryotic cells. Carbon catabolite repressor (CCR)4 and CCR4-associated factor (CAF)1 in the CCR4-NOT complex function in mRNA poly(A) tail shortening. CCR4s contain N-terminal leucine-rich repeat (LRR) motifs that interact with CAF1s in yeast, fruit fly and mammals. In silico analysis has not identified any plant CCR4 proteins that contain LRR motifs. Here, two rice CCR4 homologous genes, OsCCR4a and OsCCR4b, were identified. The isolated recombinant exonuclease-endonuclease-phosphatase domain of OsCCR4a and OsCCR4b exhibited 3'-5' exonuclease activity in vitro, and point mutation of a catalytic residue in this domain disrupted the deadenylase activity. Both OsCCR4a and OsCCR4b fluorescent fusion proteins were localized in the rice cytoplasm and nucleus, and both associated with processing bodies via their N-terminus. Binding analyses showed that OsCCR4a and OsCCR4b directly interacted with three rice CAF1 family members: OsCAF1A, OsCAF1G and OsCAF1H. The zf-MYND-like domain at the N terminus of rice CCR4 and the PXLXP motif of rice CAF1 play critical roles in OsCCR4-OsCAF1 interaction. OsCAF1 proteins, but not OsCCR4 proteins, can interact with the MIG4G domain of rice OsNOT1. Our studies thus reveal a hitherto undiscovered novel interaction pattern that connects OsCCR4 and OsCAF1 in the rice CCR4-NOT complex.

Attentional orienting and executive control are affected by different types of meditation practice.

Several studies have demonstrated the beneficial effects of meditation on attention. The present study investigated the relationship between focused attention (FA) and open monitoring (OM) meditation skills and the various functions of attention. In Experiment 1, we executed the attention network test and compared the performance of experts on dandao meditation with that of ordinary people on this test. The results indicated that the experts specializing in OM meditation demonstrated greater attentional orienting ability compared with those specializing in FA meditation and the control group. In addition, both expert groups registered improvements in their executive control abilities compared with the control group. In Experiment 2, we trained beginners in FA meditation for 3months. The results showed that the experimental group exhibited significantly enhanced executive control ability. We infer that FA meditation skills promote executive control function and OM meditation skills promote both executive control and attentional orienting functions.

Divergence of the expression and subcellular localization of CCR4-associated factor 1 (CAF1) deadenylase proteins in Oryza sativa.

Deadenylation, also called poly(A) tail shortening, is the first, rate-limiting step in the general cytoplasmic mRNA degradation in eukaryotic cells. The CCR4-NOT complex, containing the two key components carbon catabolite repressor 4 (CCR4) and CCR4-associated factor 1 (CAF1), is a major player in deadenylation. CAF1 belongs to the RNase D group in the DEDD superfamily, and is a protein conserved through evolution from yeast to humans and plants. Every higher plant, including Arabidopsis and rice, contains a CAF1 multigene family. In this study, we identified and cloned four OsCAF1 genes (OsCAF1A, OsCAF1B, OsCAF1G, and OsCAF1H) from rice. Four recombinant OsCAF1 proteins, rOsCAF1A, rOsCAF1B, rOsCAF1G, and rOsCAF1H, all exhibited 3'-5' exonuclease activity in vitro. Point mutations in the catalytic residues of each analyzed recombinant OsCAF1 proteins were shown to disrupt deadenylase activity. OsCAF1A and OsCAF1G mRNA were found to be abundant in the leaves of mature plants. Two types of OsCAF1B mRNA transcript were detected in an inverse expression pattern in various tissues. OsCAF1B was transient, induced by drought, cold, abscisic acid, and wounding treatments. OsCAF1H mRNA was not detected either under normal conditions or during most stress treatments, but only accumulated during heat stress. Four OsCAF1-reporter fusion proteins were localized in both the cytoplasm and nucleus. In addition, when green fluorescent protein fused with OsCAF1B, OsCAF1G, and OsCAF1H, respectively, fluorescent spots were observed in the nucleolus. OsCAF1B fluorescent fusion proteins were located in discrete cytoplasmic foci and fibers. We present evidences that OsCAF1B colocalizes with AtXRN4, a processing body marker, and AtKSS12, a microtubules maker, indicating that OsCAF1B is a component of the plant P-body and associate with microtubules. Our findings provide biochemical evidence that OsCAF1 proteins may be involved in the deadenylation in rice. The unique expression patterns of each OsCAF1 were observed in various tissues when undergoing abiotic stress treatments, implying that each CAF1 gene in rice plays a specific role in the development and stress response of a plant.

Subliminal spatial cues capture attention and strengthen between-object link.

According to the spreading hypothesis of object-based attention, a subliminal cue that can successfully capture attention to a location within an object should also cause attention to spread throughout the whole cued object and lead to the same-object advantage. Instead, we propose that a subliminal cue favors shifts of attention between objects and strengthens the between-object link, which is coded primarily within the dorsal pathway that governs the visual guidance of action. By adopting the two-rectangle method and using an effective subliminal cue to compare with the classic suprathreshold cue, we found a different result pattern with suprathreshold cues than with subliminal cues. The suprathreshold cue replicated the conventional location and object effects, whereas a subliminal cue led to a different-object advantage with a facilitatory location effect and a same-object advantage with an inhibitory location effect. These results support our consciousness-dependent shifting hypothesis but not the spreading hypothesis.

Efficient DNA-Driven Nanocavities for Approaching Quasi-Deterministic Strong Coupling to a Few Fluorophores.

Strong coupling between light and matter is the foundation of promising quantum photonic devices such as deterministic single photon sources, single atom lasers, and photonic quantum gates, which consist of an atom and a photonic cavity. Unlike atom-based systems, a strong coupling unit based on an emitter-plasmonic nanocavity system has the potential to bring these devices to the microchip scale at ambient conditions. However, efficiently and precisely positioning a single or a few emitters into a plasmonic nanocavity is challenging. In addition, placing a strong coupling unit on a designated substrate location is a demanding task. Here, fluorophore-modified DNA strands are utilized to drive the formation of particle-on-film plasmonic nanocavities and simultaneously integrate the fluorophores into the high field region of the nanocavities. High cavity yield and fluorophore coupling yield are demonstrated. This method is then combined with e-beam lithography to position the strong coupling units on designated locations of a substrate. Furthermore, polariton energy under the detuning of fluorophore embedded nanocavities can fit into a model consisting of three sets of two-level systems, implying vibronic modes may be involved in the strong coupling. Our system makes strong coupling units more practical on the microchip scale and at ambient conditions and provides a stable platform for investigating fluorophore-plasmonic nanocavity interaction.

Multi-Stimuli Responsive FRET Processes of Bifluorophoric AIEgens in an Amphiphilic Copolymer and Its Application to Cyanide Detection in Aqueous Media.

A novel amphiphilic aggregation-induced emission (AIE) copolymer, that is, poly(NIPAM-co-TPE-SP), consisting of N-isopropylacrylamide (NIPAM) as a hydrophilic unit and a tetraphenylethylene-spiropyran monomer (TPE-SP) as a bifluorophoric unit is reported. Upon UV exposure, the close form of non-emissive spiropyran (SP) in poly(NIPAM-co-TPE-SP) can be photo-switched to the open form of emissive merocyanine (MC) in poly(NIPAM-co-TPE-MC) in an aqueous solution, leading to ratiometric fluorescence of AIEgens between green TPE and red MC emissions at 517 and 627 nm, respectively, via Förster resonance energy transfer (FRET). Distinct FRET processes of poly(NIPAM-co-TPE-MC) can be observed under various UV and visible light irradiations, acid-base conditions, thermal treatments, and cyanide ion interactions, which are also confirmed by theoretical studies. The subtle perturbations of environmental factors, such as UV exposure, pH value, temperature, and cyanide ion, can be detected in aqueous media by distinct ratiometric fluorescence changes of the FRET behavior in the amphiphilic poly(NIPAM-co-TPE-MC). Moreover, the first FRET sensor polymer poly(NIPAM-co-TPE-MC) based on dual AIEgens of TPE and MC units is developed to show a very high selectivity and sensitivity with a low detection limit (LOD = 0.26 µM) toward the cyanide ion in water, which only contain an approximately 1% molar ratio of the bifluorophoric content and can be utilized in cellular bioimaging applications for cyanide detections.

Dissociating location-based and object-based cue validity effects in object-based attention.

Encoding predictive information and allocating visual attention according to the probability distribution is one of the marvelous achievements of our visual system. Unlike previous studies on object-based attention in which the validity of location-based cues and that of object-based cues covaried, we differentiate the two and examine whether our visual system can calculate the usefulness of the cue based on, separately and independently, the probability distribution of location on one hand and object that contains multiple locations on the other. We adopted the cueing paradigm with the double-rectangle display (Egly, Driver, & Rafal, 1994) and manipulated cue validity with respect to a particular location or the object as a whole. Results showed a spatial-cueing effect when location-based cues were informative and a same-object advantage when object-based cues were informative. We thus demonstrate here that different kinds of cue validity (location-based vs. object-based) determine different attention effects respectively (spatial-cueing effect vs. object-based advantage).

Lexical processing of Chinese sub-character components: Semantic activation of phonetic radicals as revealed by the Stroop effect.

Most Chinese characters are compounds consisting of a semantic radical indicating semantic category and a phonetic radical cuing the pronunciation of the character. Controversy surrounds whether radicals also go through the same lexical processing as characters and, critically, whether phonetic radicals involve semantic activation since they can also be characters when standing alone. Here we examined these issues using the Stroop task whereby participants responded to the ink color of the character. The key finding was that Stroop effects were found when the character itself had a meaning unrelated to color, but contained a color name phonetic radical (e.g., "guess", with the phonetic radical "cyan", on the right) or had a meaning associated with color (e.g., "pity", with the phonetic radical "blood" on the right which has a meaning related to "red"). Such Stroop effects from the phonetic radical within a character unrelated to color support that Chinese character recognition involves decomposition of characters into their constituent radicals; with each of their meanings including phonetic radicals activated independently, even though it would inevitably interfere with that of the whole character. Compared with the morphological decomposition in English whereby the semantics of the morphemes are not necessarily activated, the unavoidable semantic activation of phonetic radicals represents a unique feature in Chinese character processing.

A comparison of actual and preferred classroom environments as perceived by middle school students.

BACKGROUND: A good classroom environment can promote students' learning motivation and affect their academic efficacy and adaptation. This study compares the perceptions of Taiwanese middle school students regarding actual and preferred classroom environments and explores the association with sex and grade level. METHODS: Data were collected using cross-sectional research design from a national sample of 1932 middle school students. Data of 1897 valid questionnaires from the Chinese Elementary and Middle School Inventory of Classroom Environment were analyzed. RESULTS: The actual and preferred classroom environments perceived by students differed significantly (p < .001). The overall mean score of actual classroom environment was lower than that of preferred classroom environment. Differences between the actual and preferred environments were greater for girls than for boys (p < .001). Moreover, girls had higher scores than those of boys for both actual (p = .036) and preferred (p < .001) environments. After adjusted for region, seventh- and eighth-grade students had a higher score than that of ninth-grade students on preferred classroom environment (p = .002). CONCLUSIONS: This study identified a gap between the ideal and actual classroom environments. We suggest that the government, schools, and health education teachers improve classroom environments during school health programs to satisfy students' expectations and thus increase their learning efficacy and overall well-being.

Distinct mechanisms subserve location- and object-based visual attention.

Visual attention can be allocated to either a location or an object, named location- or object-based attention, respectively. Despite the burgeoning evidence in support of the existence of two kinds of attention, little is known about their underlying mechanisms in terms of whether they are achieved by enhancing signal strength or excluding external noises. We adopted the noise-masking paradigm in conjunction with the double-rectangle method to probe the mechanisms of location-based attention and object-based attention. Two rectangles were shown, and one end of one rectangle was cued, followed by the target appearing at (a) the cued location; (b) the uncued end of the cued rectangle; and (c) the equal-distant end of the uncued rectangle. Observers were required to detect the target that was superimposed at different levels of noise contrast. We explored how attention affects performance by assessing the threshold versus external noise contrast (TvC) functions and fitted them with a divisive inhibition model. Results show that location-based attention - lower threshold at cued location than at uncued location - was observed at all noise levels, a signature of signal enhancement. However, object-based attention - lower threshold at the uncued end of the cued than at the uncued rectangle - was found only in high-noise conditions, a signature of noise exclusion. Findings here shed a new insight into the current theories of object-based attention.

Object-based attention occurs regardless of object awareness.

In this study, we investigated whether awareness of objects is necessary for object-based guidance of attention. We used the two-rectangle method (Egly, Driver, & Rafal, 1994) to probe object-based attention and adopted the continuous flash suppression technique (Tsuchiya & Koch, 2005) to control for the visibility of the two rectangles. Our results show that object-based attention, as indexed by the same-object advantage--faster response to a target within a cued object than within a noncued object--was obtained regardless of participants' awareness of the objects. This study provides the first evidence of object-based attention under unconscious conditions by showing that the selection unit of attention can be at an object level even when these objects are invisible--a level higher than the previous evidence for a subliminally cued location. We suggest that object-based attentional guidance plays a fundamental role of binding features in both the conscious and unconscious mind.

The effects of a self-esteem program incorporated into health and physical education classes.

BACKGROUND: Self-esteem, a key construct of personality, influences thoughts, actions, and feelings. Adolescence is a critical stage to the development of self-esteem. Taiwan currently offers no self-esteem building curriculum in the public education system. Therefore, incorporating self-esteem-related teaching activities into the existing curriculum represents a feasible approach to enhance self-esteem in middle school students. PURPOSE: This study aimed to explore the effects on junior high school students' self-esteem of a self-esteem program incorporated into the general health and physical education curriculum. METHODS: A quasi-experimental research design was used, and 184 seventh-grade students at two junior high schools in Taipei City were randomly selected and separated into two groups. The experimental group received one 32-week self-esteem program incorporated into their regular health and physical education curriculum, which was administered in three 45-minute-session classes each week. The control group received the regular health and physical education with no specially designed elements. During the week before the intervention began and the week after its conclusion, each participant's global and academic, physical, social, and family self-esteem was assessed. Data were analyzed using analysis of covariance. RESULTS: For all participants, the experimental group was significantly superior to the control group in respect to physical self-esteem (p = .02). For girls, the experimental group was significantly superior to the control group in family self-esteem (p = .02). However, there was no significant difference between the two groups in terms of global self-esteem. CONCLUSIONS AND IMPLICATIONS FOR PRACTICE: This study provides preliminary evidence that incorporating self-esteem activities into the regular school health and physical education curriculum can result in minor effects in students' physical self-esteem and family self-esteem. Findings may provide teachers and school administrators with information to help them design programs to improve students' self-esteem. This study also reminds health professionals to focus on providing self-esteem-building programs when working with adolescent clients.

Location- and object-based inhibition of return are affected by different kinds of working memory.

Castel, Pratt, and Craik (2003) have shown that inhibition of return (IOR, the delayed response to a recently cued item) is disrupted by a secondary task that involves spatial working memory (WM), and they suggest that IOR is mediated by spatial WM. However, they did not specify what kind of IOR was involved. We used a dual-task paradigm to examine whether the two kinds of IOR (location- and object-based IOR) are affected by two kinds of secondary task that involve spatial and nonspatial WM, respectively. The results show that location-based IOR was disrupted by a spatial secondary task while the object-based IOR was disrupted by a nonspatial secondary task. The present study further elaborates the conclusion of Castel et al. (2003) by differentiating the effect of the two kinds of WM (spatial vs. nonspatial) on the two kinds of IOR (location based vs. object based).