A unifying framework for functional organization in early and higher ventral visual cortex.

A key feature of cortical systems is functional organization: the arrangement of functionally distinct neurons in characteristic spatial patterns. However, the principles underlying the emergence of functional organization in the cortex are poorly understood. Here, we develop the topographic deep artificial neural network (TDANN), the first model to predict several aspects of the functional organization of multiple cortical areas in the primate visual system. We analyze the factors driving the TDANN's success and find that it balances two objectives: learning a task-general sensory representation and maximizing the spatial smoothness of responses according to a metric that scales with cortical surface area. In turn, the representations learned by the TDANN are more brain-like than in spatially unconstrained models. Finally, we provide evidence that the TDANN's functional organization balances performance with between-area connection length. Our results offer a unified principle for understanding the functional organization of the primate ventral visual system.

FAB1C, a phosphatidylinositol 3-phosphate 5-kinase, interacts with PIN-FORMEDs and modulates their lytic trafficking in Arabidopsis.

PIN-FORMEDs (PINs) are auxin efflux carriers that asymmetrically target the plasma membrane (PM) and are critical for forming local auxin gradients and auxin responses. While the cytoplasmic hydrophilic loop domain of PIN (PIN-HL) is known to include some molecular cues (e.g., phosphorylation) for the modulation of PIN's intracellular trafficking and activity, the complexity of auxin responses suggests that additional regulatory modules may operate in the PIN-HL domain. Here, we have identified and characterized a PIN-HL-interacting protein (PIP) called FORMATION OF APLOID AND BINUCLEATE CELL 1C (FAB1C), a phosphatidylinositol-3-phosphate 5-kinase, which modulates PIN's lytic trafficking. FAB1C directly interacts with PIN-HL and is required for the polarity establishment and vacuolar trafficking of PINs. Unphosphorylated forms of PIN2 interact more readily with FAB1C and are more susceptible to vacuolar lytic trafficking compared to phosphorylated forms. FAB1C also affected lateral root formation by modulating the abundance of periclinally localized PIN1 and auxin maximum in the growing lateral root primordium. These findings suggest that a membrane-lipid modifier can target the cargo-including vesicle by directly interacting with the cargo and modulate its trafficking depending on the cargo's phosphorylation status.

The complete mitochondrial genome of an Antarctic moss, Andreaea regularis Müll. Hal. 1890 (Andreaeaceae).

In the present study, we determined the complete mitochondrial genome of Andreaea regularis Müll. Hal. 1890, a lantern moss of the genus Andreaea Hedw. (Andreaeaceae). The A. regularis mitochondrial genome, with a total length of 118,833 bp, consists of 40 protein-coding genes, 3 ribosomal RNA genes, and 24 transfer RNA genes. A phylogenetic tree constructed with 19 complete mitochondrial genomes composed of liverworts, hornworts, and 15 mosses showed that Andreaeales formed the closest sister to Sphagnales before divergence of the remaining moss groups, indicating A. regularis being one of the earliest mosses. Our findings could be beneficial to investigate the bryophyte evolution.

A Unifying Principle for the Functional Organization of Visual Cortex.

A key feature of many cortical systems is functional organization: the arrangement of neurons with specific functional properties in characteristic spatial patterns across the cortical surface. However, the principles underlying the emergence and utility of functional organization are poorly understood. Here we develop the Topographic Deep Artificial Neural Network (TDANN), the first unified model to accurately predict the functional organization of multiple cortical areas in the primate visual system. We analyze the key factors responsible for the TDANN's success and find that it strikes a balance between two specific objectives: achieving a task-general sensory representation that is self-supervised, and maximizing the smoothness of responses across the cortical sheet according to a metric that scales relative to cortical surface area. In turn, the representations learned by the TDANN are lower dimensional and more brain-like than those in models that lack a spatial smoothness constraint. Finally, we provide evidence that the TDANN's functional organization balances performance with inter-area connection length, and use the resulting models for a proof-of-principle optimization of cortical prosthetic design. Our results thus offer a unified principle for understanding functional organization and a novel view of the functional role of the visual system in particular.

Calcium-dependent protein kinase 29 modulates PIN-FORMED polarity and Arabidopsis development via its own phosphorylation code.

PIN-FORMED (PIN)-mediated polar auxin transport (PAT) is involved in key developmental processes in plants. Various internal and external cues influence plant development via the modulation of intracellular PIN polarity and, thus, the direction of PAT, but the mechanisms underlying these processes remain largely unknown. PIN proteins harbor a hydrophilic loop (HL) that has important regulatory functions; here, we used the HL as bait in protein pulldown screening for modulators of intracellular PIN trafficking in Arabidopsis thaliana. Calcium-dependent protein kinase 29 (CPK29), a Ca2+-dependent protein kinase, was identified and shown to phosphorylate specific target residues on the PIN-HL that were not phosphorylated by other kinases. Furthermore, loss of CPK29 or mutations of the phospho-target residues in PIN-HLs significantly compromised intracellular PIN trafficking and polarity, causing defects in PIN-mediated auxin redistribution and biological processes such as lateral root formation, root twisting, hypocotyl gravitropism, phyllotaxis, and reproductive development. These findings indicate that CPK29 directly interprets Ca2+ signals from internal and external triggers, resulting in the modulation of PIN trafficking and auxin responses.

Application of Adaptive Wave Cancellation Underwater to a Piezoelectric-Material-Based Multilayer Sensor.

This paper concerns the use of adaptive wave cancellation in a new multilayer smart skin sensor to attenuate the primary low-frequency noise underwater. The proposed multilayered system is designed with a piezoelectric actuator (Pb(In1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 composite) and two layers of polyvinylidene fluoride to accelerate wave absorption. Furthermore, the use of a combination of an adaptive control scheme and a time-delay signal separation method has the potential to provide the proposed absorber system with a wave cancellation capability and thereby enable the absorber system to respond to environmental changes underwater. The use of smart piezoelectric materials and an adaptive control approach enables the absorber system to achieve the high attenuation level of the reflected waves, unlike typical absorber systems based on active noise control. Echo reduction experiments showed that the proposed piezoelectric-based multilayer sensor with an adaptive controller could attenuate reflected wave signals effectively.

Developmental Programming of Thermonastic Leaf Movement.

Plants exhibit diverse polar behaviors in response to directional and nondirectional environmental signals, termed tropic and nastic movements, respectively. The ways in which plants incorporate directional information into tropic behaviors is well understood, but it is less well understood how nondirectional stimuli, such as ambient temperatures, specify the polarity of nastic behaviors. Here, we demonstrate that a developmentally programmed polarity of auxin flow underlies thermo-induced leaf hyponasty in Arabidopsis (Arabidopsis thaliana). In warm environments, PHYTOCHROME-INTERACTING FACTOR4 (PIF4) stimulates auxin production in the leaf. This results in the accumulation of auxin in leaf petioles, where PIF4 directly activates a gene encoding the PINOID (PID) protein kinase. PID is involved in polarization of the auxin transporter PIN-FORMED3 to the outer membranes of petiole cells. Notably, the leaf polarity-determining ASYMMETRIC LEAVES1 (AS1) directs the induction of PID to occur predominantly in the abaxial petiole region. These observations indicate that the integration of PIF4-mediated auxin biosynthesis and polar transport, and the AS1-mediated developmental shaping of polar auxin flow, coordinate leaf thermonasty, which facilitates leaf cooling in warm environments. We believe that leaf thermonasty is a suitable model system for studying the developmental programming of environmental adaptation in plants.

Intracellularly Localized PIN-FORMED8 Promotes Lateral Root Emergence in Arabidopsis.

PIN-FORMED (PIN) auxin efflux carriers with a long central hydrophilic loop (long PINs) have been implicated in organogenesis. However, the role of short hydrophilic loop PINs (short PINs) in organogenesis is largely unknown. In this study, we investigated the role of a short PIN, PIN8, in lateral root (LR) development in Arabidopsis thaliana. The loss-of-function mutation in PIN8 significantly decreased LR density, mostly by affecting the emergence stage. PIN8 showed a sporadic expression pattern along the root vascular cells in the phloem, where the PIN8 protein predominantly localized to intracellular compartments. During LR primordium development, PIN8 was expressed at the late stage. Plasma membrane (PM)-localized long PINs suppressed LR formation when expressed in the PIN8 domain. Conversely, an auxin influx carrier, AUX1, restored the wild-type (WT) LR density when expressed in the PIN8 domain of the pin8 mutant root. Moreover, LR emergence was considerably inhibited when AXR2-1, the dominant negative form of Aux/IAA7, compromised auxin signaling in the PIN8 domain. Consistent with these observations, the expression of many genes implicated in late LR development was suppressed in the pin8 mutant compared with the WT. Our results suggest that the intracellularly localized PIN8 affects LR development most likely by modulating intracellular auxin translocation. Thus, the function of PIN8 is distinctive from that of PM-localized long PINs, where they generate local auxin gradients for organogenesis by conducting cell-to-cell auxin reflux.

Cell wall-associated ROOT HAIR SPECIFIC 10, a proline-rich receptor-like kinase, is a negative modulator of Arabidopsis root hair growth.

Plant cell growth is restricted by the cell wall, and cell wall dynamics act as signals for the cytoplasmic and nuclear events of cell growth. Among various receptor kinases, ROOT HAIR SPECIFIC 10 (RHS10) belongs to a poorly known receptor kinase subfamily with a proline-rich extracellular domain. Here, we report that RHS10 defines the root hair length of Arabidopsis thaliana by negatively regulating hair growth. RHS10 modulates the duration of root hair growth rather than the growth rate. As poplar and rice RHS10 orthologs also showed a root hair-inhibitory function, this receptor kinase-mediated function appears to be conserved in angiosperms. RHS10 showed a strong association with the cell wall, most probably through its extracellular proline-rich domain (ECD). Deletion analysis of the ECD demonstrated that a minimal extracellular part, which includes a few proline residues, is required for RHS10-mediated root hair inhibition. RHS10 suppressed the accumulation of reactive oxygen species (ROS) in the root, which are necessary for root hair growth. A yeast two-hybrid screening identified an RNase (RNS2) as a putative downstream target of RHS10. Accordingly, RHS10 overexpression decreased and RHS10 loss increased RNA levels in the hair-growing root region. Our results suggest that RHS10 mediates cell wall-associated signals to maintain proper root hair length, at least in part by regulating RNA catabolism and ROS accumulation.