SummaryIn order to understand the molecular genetic mechanisms of rice (Oryza sativa) organ development, we studied the narrow leaf2 narrow leaf3 (nal2 nal3; hereafter nal2/3) double mutant, which produces narrow-curly leaves, more tillers, fewer lateral roots, opened spikelets and narrow-thin grains.We found that narrow-curly leaves resulted mainly from reduced lateral-axis outgrowth with fewer longitudinal veins and more, larger bulliform cells. Opened spikelets, possibly caused by marginal deformity in the lemma, gave rise to narrow-thin grains.Map-based cloning revealed that NAL2 and NAL3 are paralogs that encode an identical OsWOX3A (OsNS) transcriptional activator, homologous to NARROW SHEATH1 (NS1) and NS2 in maize and PRESSED FLOWER in Arabidopsis. OsWOX3A is expressed in the vascular tissues of various organs, where nal2/3 mutant phenotypes were displayed. Expression levels of several leaf development-associated genes were altered in nal2/3, and auxin transportrelated genes were significantly changed, leading to pin mutant-like phenotypes such as more tillers and fewer lateral roots.OsWOX3A is involved in organ development in rice, lateral-axis outgrowth and vascular patterning in leaves, lemma and palea morphogenesis in spikelets, and development of tillers and lateral roots.

Photosynthetic organisms exhibit a green color due to the accumulation of chlorophyll pigments in chloroplasts. Mg-protoporphyrin IX chelatase (Mg-chelatase) comprises three subunits (ChlH, ChlD and ChlI) and catalyzes the insertion of Mg(2+) into protoporphyrin IX, the last common intermediate precursor in both chlorophyll and heme biosyntheses, to produce Mg-protoporphyrin IX (MgProto). Chlorophyll deficiency in higher plants results in chlorina (yellowish-green) phenotype. To date, 10 chlorina (chl) mutants have been isolated in rice, but the corresponding genes have not yet been identified. Rice Chl1 and Chl9 genes were mapped to chromosome 3 and isolated by map-based cloning. A missense mutation occurred in a highly conserved amino acid of ChlD in the chl1 mutant and ChlI in the chl9 mutant. Ultrastructural analyses have revealed that the grana are poorly stacked, resulting in the underdevelopment of chloroplasts. In the seedlings fed with aminolevulinate-dipyridyl in darkness, MgProto levels in the chl1 and chl9 mutants decreased up to 25% and 31% of that in wild-type, respectively, indicating that the Mg-chelatase activity is significantly reduced, causing the eventual decrease in chlorophyll synthesis. Furthermore, Northern blot analysis indicated that the nuclear genes encoding the three subunits of Mg-chelatase and LhcpII in chl1 mutant are expressed about 2-fold higher than those in WT, but are not altered in the chl9 mutant. This result indicates that the ChlD subunit participates in negative feedback regulation of plastid-to-nucleus in the expression of nuclear genes encoding chloroplast proteins, but not the ChlI subunit.

These authors contributed equally to the work. SUMMARYNADPH:protochlorophyllide oxidoreductase (POR) catalyzes photoreduction of protochlorophyllide (Pchlide) to chlorophyllide in chlorophyll (Chl) synthesis, and is required for prolamellar body (PLB) formation in etioplasts. Rice faded green leaf (fgl) mutants develop yellow/white leaf variegation and necrotic lesions during leaf elongation in field-grown plants. Map-based cloning revealed that FGL encodes OsPORB, one of two rice POR isoforms. In fgl, etiolated seedlings contained smaller PLBs in etioplasts, and lower levels of total and photoactive Pchlide. Under constant or high light (HL) conditions, newly emerging green leaves rapidly turned yellow and formed lesions. Increased levels of non-photoactive Pchlide, which acts as a photosensitizer, may cause reactive oxygen accumulation and lesion formation. OsPORA expression is repressed by light and OsPORB expression is regulated in a circadian rhythm in short-day conditions. OsPORA was expressed at high levels in developing leaves and decreased dramatically in fully mature leaves, whereas OsPORB expression was relatively constant throughout leaf development, similar to expression patterns of AtPORA and AtPORB in Arabidopsis. However, OsPORB expression is rapidly upregulated by HL treatment, similar to the fluence rate-dependent regulation of AtPORC. This suggests that OsPORB function is equivalent to both AtPORB and AtPORC functions. Our results demonstrate that OsPORB is essential for maintaining light-dependent Chl synthesis throughout leaf development, especially under HL conditions, whereas OsPORA mainly functions in the early stages of leaf development. Developmentally and physiologically distinct roles of monocot OsPORs are discussed by comparing with those of dicot AtPORs.

Basal ganglia (BG) circuits orchestrate complex motor behaviors predominantly via inhibitory synaptic outputs. Although these inhibitory BG outputs are known to reduce the excitability of postsynaptic target neurons, precisely how this change impairs motor performance remains poorly understood. Here, we show that optogenetic photostimulation of inhibitory BG inputs from the globus pallidus induces a surge of action potentials in the ventrolateral thalamic (VL) neurons and muscle contractions during the post-inhibitory period. Reduction of the neuronal population with this post-inhibitory rebound firing by knockout of T-type Ca channels or photoinhibition abolishes multiple motor responses induced by the inhibitory BG input. In a low dopamine state, the number of VL neurons showing post-inhibitory firing increases, while reducing the number of active VL neurons via photoinhibition of BG input, effectively prevents Parkinson disease (PD)-like motor symptoms. Thus, BG inhibitory input generates excitatory motor signals in the thalamus and, in excess, promotes PD-like motor abnormalities. VIDEO ABSTRACT.

Interscalene block performed under ultrasound guidance with 0.75% ropivacaine 5 mL showed analgesic efficacy similar to that with 0.75% ropivacaine 10 mL, but with a lower incidence of hemidiaphragmatic paralysis.

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The development of three-dimensional polymeric systems capable of mimicking the extracellular matrix is critical for advancing tissue engineering. To achieve these objectives, three-dimensional fibrous scaffolds with "clay"-like properties were successfully developed by coaxially electrospinning polystyrene (PS) and poly(ε-caprolactone) (PCL) and selective leaching. As PS is known to be nonbiodegradable and vulnerable to mechanical stress, PS layers present at the outer surface were removed using a "selective leaching" process. The fibrous PCL scaffolds that remained after the leaching step exhibited highly advantageous characteristics as a tissue engineering scaffold, including moldability (i.e., clay-like), flexibility, and three-dimensional structure (i.e., cotton-like). More so, the "clay-like" PCL fibrous scaffolds could be shaped into any desired form, and the microenvironment within the clay scaffolds was highly favorable for cell expansion both in vitro and in vivo. These "electrospun-clay" scaffolds overcome the current limitations of conventional electrospun, sheet-like scaffolds, which are structurally inflexible. Therefore, this work extends the scope of electrospun fibrous scaffolds toward a variety of tissue engineering applications.

HighlightAmong the lesion mimic mutants in rice, the spotted leaf3 (spl3) locus was identified by map-based cloning that encodes OsMAPKKK1. SPL3 was found to be involved in ABA-responsive signalling and to promote leaf yellowing during senescence.