Biology subjects

Ito, S.

Publications and source records attributed to Ito, S..

At least 37 records · Page 2Linked to original sources

bioRxiv2025

Metformin Does Not Attenuate Angiotensin II-Induced Aortic Aneurysms in Low-Density Lipoprotein Receptor Deficient Mice

BackgroundMetformin, a biguanide antihyperglycemic agent, prevents angiotensin II (AngII)-induced abdominal aortic aneurysm formation in apolipoprotein E-deficient (ApoE-/-) mice. Low-density lipoprotein receptor-deficient (LDLR-/-) mice are also widely used as a hypercholesterolemic model, which more closely mimics the lipoprotein profile of patients with hypercholesterolemia than ApoE-/- mice. In addition, LDLR-/- mice exhibit characteristics of glucose metabolism that are distinct from ApoE-/- mice. However, it remains unknown whether metformin suppresses AngII-induced aortic aneurysm formation in LDLR-/- mice. MethodsMale LDLR-/- mice at 9 weeks of age were administered either vehicle or metformin in drinking water and fed a Western diet. Subsequently, AngII was infused into mice for 4 weeks. Plasma metformin concentrations were measured by mass spectrometry. Maximal aortic diameters and areas were measured ex vivo. ResultsMass spectrometry analysis determined plasma metformin concentrations in mice administered the drug. Metformin administration resulted in lower body weight compared to the vehicle group, indicating effective metformin administration. However, ex vivo measurements demonstrated that metformin did not reduce aortic diameters in the suprarenal abdominal region. In addition, metformin failed to prevent AngII-induced ascending aortic dilatations. ConclusionMetformin did not attenuate AngII-induced aortic aneurysm formation in either the ascending or suprarenal abdominal region of LDLR-/- mice.

pathology↗

bioRxiv2025

β-aminopropionitrile-induced thoracic aortopathy is refractory to cilostazol and sildenafil in mice

Thoracic aortopathies are life-threatening diseases including aneurysm, dissection, and rupture. Phosphodiesterases (PDEs) regulate intracellular cyclic nucleotide concentrations. Recent studies report the influences of cilostazol, a PDE3 inhibitor, and sildenafil, a PDE5 inhibitor, on abdominal aortic aneurysm formation. However, their impacts on thoracic aortopathy remain unknown. In this study, we investigated whether cilostazol and sildenafil affect thoracic aortopathy induced by {beta}-aminopropionitrile (BAPN) administration in mice. Bulk RNA sequencing analysis revealed that BAPN administration upregulated Pde3a transcription in the ascending aorta and Pde5a in both ascending and descending regions before thoracic aortopathy formation. Next, we tested the effects of cilostazol or sildenafil on BAPN-induced thoracic aortopathy. BAPN-administered mice were fed a diet supplemented with either cilostazol or sildenafil. Mass spectrometry measurements determined the presence of cilostazol or sildenafil in the plasma of mice fed drug-supplemented diets. However, neither drug altered BAPN-induced aortic rupture nor aneurysm formation and progression. These results provide evidence that cilostazol and sildenafil did not influence BAPN-induced thoracic aortopathy in mice.

pathology↗

bioRxiv2025

Smooth Muscle Cells and Fibroblasts in the Proximal Thoracic Aorta Exhibit Minor Differences Between Embryonic Origins in Angiotensin II-driven Transcriptional Alterations

BackgroundThoracic aortopathy is influenced by angiotensin II (AngII) and exhibits regional heterogeneity with the proximal region of the thoracic aorta being susceptible. Smooth muscle cells (SMCs) and selected fibroblasts in this region are derived from two embryonic origins: second heart field (SHF) and cardiac neural crest (CNC). While our previous study revealed a critical role of SHF-derived cells in AngII-mediated aortopathy formation, the contribution of CNC-derived cells remains unclear. MethodsMef2c-Cre R26RmT/mG mice were infused with AngII (1,000 ng/kg/min). Proximal thoracic aortas were harvested at baseline or after 3 days of infusion, representing the prepathological phase. Cells were sorted by origins using mGFP (SHF-derived) and mTomato (other origins, nSHF-derived) signals, respectively. After sorting cells by origin, single-cell RNA sequencing was performed and analyzed. ResultsShort-term AngII infusion induced significant transcriptomic changes in both SHF- and nSHF-derived SMCs, but differences between origins were modest. Fibroblast transcriptomes also underwent notable changes by AngII infusion, but differences between SHF and nSHF origins remained modest. Interestingly, AngII infusion resulted in the emergence of a new fibroblast sub-population. Several molecules related to the extracellular matrix, such as Eln and Col3a1, were downregulated in SHF-derived fibroblasts compared to nSHF-derived fibroblasts in the new subcluster. ConclusionFibroblasts in the new subcluster exhibited lineage-specific differences in extracellular matrix-related genes; however, overall transcriptomic differences between origins in SMCs and fibroblasts in response to AngII were modest in the pre-pathological phase of AngII-induced thoracic aortopathy. GRAPHIC ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=174 SRC="FIGDIR/small/610985v1_ufig1.gif" ALT="Figure 1"> View larger version (38K): org.highwire.dtl.DTLVardef@17c2e3corg.highwire.dtl.DTLVardef@1bf9517org.highwire.dtl.DTLVardef@d51aedorg.highwire.dtl.DTLVardef@dac951_HPS_FORMAT_FIGEXP M_FIG C_FIG

pathology↗

bioRxiv2025

Characterization of auditory responsive neurons in the mouse superior colliculus to naturalistic sounds

Locating the source of a specific sound in a complex environment and determining its saliency is critical for survival. The superior colliculus (SC), a sensorimotor midbrain structure, plays an important role in sound localization and has been shown to have a topographic map of the auditory space in a range of species. In mice, previous studies using broadband white noise stimuli found that neurons use high-frequency monaural spectral cues and interaural level differences (ILDs) to compute spatially restricted receptive fields (RFs), and that these RFs are organized topographically along the azimuth. However, in a naturalistic environment, the auditory stimuli that an animal encounters may have rich spectral components; however, these sound sources can still be localized efficiently. It remains unknown whether and how the SC neurons respond to naturalistic sounds and, in turn, compute a spatially restricted RF. Here, we show results from large-scale in vivo physiological recordings of SC neurons in response to white noise, naturalistic ultrasonic pup calls and chirps. We find that mouse SC auditory neurons respond to pup calls with distinct temporal patterns and a spatial preference predominantly at [~]60 degrees in contralateral azimuth. In addition, we categorized auditory SC neurons based on their spectrotemporal receptive field patterns and demonstrated that there are at least 4 distinct subtypes of auditory responsive SC neurons. Significance StatementThe superior colliculus (SC) receives visual and auditory information that is used to localize objects. While the organization and composition of visually responsive SC neurons is well described, much less is known about the types and response properties of auditory SC neurons. Here, we presented white noise, ultrasonic mouse pup calls, and chirp stimuli to mice while recording from SC neurons. Analysis of neuronal responses defines 4 distinct classes of auditory neurons. We also show that while auditory neurons respond to naturalistic stimuli, these responses mainly occur when presented from the side but not the front of the animal. These results lead to the hypothesis that mice use different strategies to localize sound depending on the spectral composition of the source.

neuroscience↗

bioRxiv2024

Harnessing the Biosynthetic Diversity of Actinomycetes: Discovery of Unique Natural Products through Comparative Genomic and Metabolic Analysis

Actinomycetes, rich in biosynthetic gene clusters (BGCs), are important sources of natural products (NPs). However, the rate of discovering novel NPs from actinomycetes has declined, indicating the need for a new strategy to obtain NPs. Herein, we present a strategy for the efficient discovery of novel NPs. First, we performed a comprehensive analysis of BGCs in actinomycetes, evaluating the average number and types of BGCs per genus to identify prolific NP producers. Our analysis revealed that certain actinomycetes strains, such as those in the family Pseudonocardiaceae, possess a greater number of BGCs than Streptomyces. In addition, these strains tend to possess strain-specific BGCs compared with others. To facilitate the identification of strain-specific compounds, we developed a comparative metabolic analysis method using molecular networking. Applying this method to eight Pseudonocardiaceae strains, we successfully discovered two novel peptides, lentindoles A (1) and B (2), featuring a 6/5/6 and 6/5/5 tricyclic ring system, respectively, along with their possible biosynthetic precursor, lentindole C (3). Our result demonstrates that the effectiveness of our developed strategy, which is expected to accelerate the discovery of novel NPs.

microbiology↗

bioRxiv2024

High-throughput robotic isolation of human iPS cell clones reveals frequent homozygous induction of identical genetic manipulations by CRISPR-Cas9

Genome editing in human iPS cells is a powerful approach in regenerative medicine. CRISPR-Cas9 is the most common genome editing tool, but it often induces byproduct insertions and deletions in addition to the desired edits. Therefore, genome editing of iPS cells produces diverse genotypes. Existing assays mostly analyze genome editing results in cell populations, but not in single cells. However, systematic profiling of genome editing outcomes in single iPS cells was lacking. In this study, we developed a method for high-throughput iPS cell clone isolation based on the precise robotic picking of cell clumps derived from single cells grown in extracellular matrices. We analyzed over 1,000 genome-edited iPS cell clones and found that homozygous editing was much more frequent than heterozygous editing. We also observed frequent homozygous induction of identical genetic manipulations, including insertions and deletions. Our new cloning method and findings will facilitate the application of genome editing to human iPS cells.

bioengineering↗

bioRxiv2024

A florigen-expressing subpopulation of companion cells expresses other small proteins and reveals a nitrogen-sensitive FT repressor

The precise onset of flowering is crucial to ensure successful plant reproduction. The gene FLOWERING LOCUS T (FT) encodes florigen, a mobile signal produced in leaves that initiates flowering at the shoot apical meristem. In response to seasonal changes, FT is induced in phloem companion cells located in distal leaf regions. Thus far, a detailed molecular characterization of the FT-expressing cells has been lacking. Here, we used bulk nuclei RNA-seq and single nuclei RNA (snRNA)-seq to investigate gene expression in FT-expressing cells and other phloem companion cells. Our bulk nuclei RNA-seq demonstrated that FT-expressing cells in cotyledons and true leaves showed differences especially in FT repressor genes. Within the true leaves, our snRNA-seq analysis revealed that companion cells with high FT expression form a unique cluster in which many genes involved in ATP biosynthesis are highly upregulated. The cluster also expresses other genes encoding small proteins, including the flowering and stem growth inducer FPF1-LIKE PROTEIN 1 (FLP1) and the anti-florigen BROTHER OF FT AND TFL1 (BFT). In addition, we found that the promoters of FT and the genes co-expressed with FT in the cluster were enriched for the consensus binding motifs of NITRATE-INDUCIBLE GARP-TYPE TRANSCRIPTIONAL REPRESSOR 1 (NIGT1). Overexpression of the paralogous NIGT1.2 and NIGT1.4 repressed FT expression and significantly delayed flowering under nitrogen-rich conditions, consistent with NIGT1s acting as nitrogen-dependent FT repressors. Taken together, our results demonstrate that major FT-expressing cells show a distinct expression profile that suggests that these cells may produce multiple systemic signals to regulate plant growth and development.

plant biology↗

bioRxiv2024

Lipogenic Lung Fibroblast-derived Extracellular Vesicles Mitigate Cigarette Smoke-Induced Chronic Obstructive Pulmonary Disease Pathologies through LAT1-mediated Alveolar Type II Cell Restoration

Emerging research has revealed specific cellular aberrations in Chronic Obstructive Pulmonary Disease (COPD), with a particular focus on alveolar type 2 (AT2) cells, which play a pivotal role in the restoration of damaged lung tissue and promotion of normal cellular differentiation. Lipofibroblasts (LipoFBs), which are stromal fibroblasts that house lipid droplets, have been identified in close proximity to AT2 cells and have been demonstrated to support AT2 function. In this study, we present a comprehensive investigation into the therapeutic potential of extracellular vesicles (EVs) derived from LipoFBs (LipoFB-EVs) in COPD treatment. They effectively mitigate key COPD pathologies such as cellular senescence and inflammatory responses in lung epithelial cells. This is achieved by reducing reactive oxygen species (ROS) levels and modulating DNA damage response pathways. Moreover, LipoFB-EVs demonstrate antifibrotic properties by inhibiting TGF-{beta}-induced myofibroblast differentiation, surpassing conventional antifibrotic drugs. They also aid in restoring impaired AT2 stem cells, which are crucial for lung homeostasis, by enhancing their viability, colony-forming ability, and proliferation. Furthermore, we identify the presence of L-type amino acid transporter 1 (LAT1) within LipoFB-EVs, which mediates amino acid uptake, particularly leucine transport, and contributes to the restoration of AT2 cell dysfunction. Importantly, the administration of LipoFB-EVs in murine models of COPD resulted in significant improvements in airway inflammation, remodeling, obstruction, cellular senescence, and alveolar emphysema induced by both short- and long-term CS exposure. Overall, our findings highlight the therapeutic potential of LipoFB-EVs as a novel regenerative therapy for COPD, offering promising avenues for future clinical interventions.

molecular biology↗

bioRxiv2024

Minimizing command timing volatility is a key factor in skilled actions

Variability between movements prevents the best athletes from making a perfect shot every time. While fluctuations in the amplitude of neural sensory inputs and motor outputs are thought to be primarily responsible, they only account for a fraction of the observed variability. Here, we propose that a significant portion of the variability is due to imprecisely timed motor commands. This command timing volatility theory best explained the three peaks observed in the force variabilitys time-series in discrete reaching movements and during periodic force control. Furthermore, we show how the timing volatility in the non-dominant arms muscles is larger than in the dominant arm, then develop a variability index that estimates the arms timing volatility via its variability during circle tracing. The difference in the variability index between the left and right hands accurately predicts the Edinburgh Quotient, suggesting a relationship between handedness and the command timing volatility of the left- and right-hands. Lastly, we constructed a simulation of reaching movements made by an arm controlled by muscles whose command timing was made incrementally more volatile. As timing volatility increased, aiming became less precise and movements jerkier. Such impairments during reaching are reported in patients with different neuronal diseases that damage any brain regions critical to motor timing, suggesting that essential aspects of these symptoms may be caused by excessive timing volatility. Our theory provides a unifying computational perspective of movement variability in healthy and diseased individuals that is essential to understanding the control of movements.

neuroscience↗

bioRxiv2024

Model-based analysis on the generation of the circadian rhythm of the bioluminescence reporter activities in duckweed

Bioluminescence monitoring techniques are widely used to study the gene expression dynamics in living plants. Monitoring the bioluminescence from a luciferase gene under the control of a circadian promoter is indispensable for examining plant circadian systems. The bioluminescence monitoring technique was successfully applied to physiological studies of circadian rhythms in duckweed plants. It has been reported that a luciferase gene under a constitutive promoter also exhibits a bioluminescent circadian rhythm in duckweed. However, the mechanisms underlying rhythm generation remain unknown. In this study, we performed a model-based analysis to evaluate the machinery that generates the bioluminescence rhythm. We hypothesized the rhythmic factor of three aspects regarding the bioluminescence intensities of luciferase in cells: luminescence efficiency, production rate, and degradation rate. Theoretically, if the latter two are involved in rhythm generation, the difference in luciferase stability affects the amplitude and phase relations of the bioluminescence rhythm. Luciferase stability is irrelevant to these rhythm properties if only the luminescence efficiency is involved. First, we simulated the bioluminescence rhythms of two luciferases with different stabilities associated with each of three rhythmic factors. Luciferase stability was set based on the reported values for Emerald-luciferase and Emerald-luciferase-PEST. We then experimentally examined the bioluminescence rhythms of reporters of these luciferases driven by the CAULIFLOWER MOSAIC VIRUS 35S promoter in the duckweed Lemna japonica. Their circadian properties matched those obtained from the simulation of the luminescence efficiency. This supports the view that cells in duckweed show circadian changes in physiological conditions associated with the luciferase enzyme reaction.

plant biology↗

bioRxiv2024

Florigen-producing cells express FPF1-LIKE PROTEIN 1 that accelerates flowering and stem growth in long days with sunlight red/far-red ratio in Arabidopsis

Seasonal changes in spring induce flowering by expressing the florigen, FLOWERING LOCUS T (FT), in Arabidopsis. FT is expressed in unique phloem companion cells with unknown characteristics. The question of which genes are co-expressed with FT and whether they have roles in flowering remains elusive. Through tissue-specific translatome analysis, we discovered that under long-day conditions with the natural sunlight red/far-red ratio, the FT-producing cells express a gene encoding FPF1-LIKE PROTEIN 1 (FLP1). The master FT regulator, CONSTANS (CO), controls FLP1 expression, suggesting FLP1s involvement in the photoperiod pathway. FLP1 promotes early flowering independently of FT, is active in the shoot apical meristem, and induces the expression of SEPALLATA 3 (SEP3), a key E-class homeotic gene. Unlike FT, FLP1 facilitates inflorescence stem elongation. Our cumulative evidence indicates that FLP1 may act as a mobile signal. Thus, FLP1 orchestrates floral initiation together with FT and promotes inflorescence stem elongation during reproductive transitions.

plant biology↗

bioRxiv2024

Plaque-associated endogenous IgG and its impact on immunohistochemical detection of mouse monoclonal IgG antibodies in mouse models of Alzheimer's disease

Experimental studies for Alzheimers disease (AD) have largely depended on transgenic mice with {beta}-amyloidosis. Here, we report plaque-associated endogenous immunoglobulin G (PA-IgG) and its impact on indirect immunohistochemical detection of mouse monoclonal IgG antibodies (Ms monoclonal IgG Abs) in the brain of AD mouse models. Immunostaining for Ms IgG in AD mouse models demonstrated endogenous IgG in the brain parenchyma accumulated on microglia associated with amyloid {beta} (A{beta}) plaques and/or A{beta} plaques themselves. This PA-IgG caused robust off-target binding of secondary Abs against Ms IgG (H+L) in indirect immunohistochemistry using Ms monoclonal IgG Abs. Blocking with Fab fragments of anti-Ms IgG (H+L) Ab was not effective against off-target binding. Unexpectedly, we found that secondary Abs that specifically recognize Ms IgG1, 2a, 2b, and 3 did not cause off-target binding on frozen brain sections of AppNL-G-F/NL-G-Fmice, and enabled specific labeling of Ms monoclonal IgG Abs in the AD mouse model brains. We further demonstrated that indirect detection with a conventional secondary Ab against Ms IgG (H+L) Ab could lead to erroneous conclusions regarding A{beta} plaque burden and phosphorylated tau accumulation in AppNL-G-F/NL-G-Fmice, and the use of Ms IgG subclass specific secondary Abs allowed to avoid the inevitable impediment caused by the endogenous IgG accumulation. Specific indirect detection of Ms monoclonal IgG Abs in AD mouse models by the use of secondary Abs against Ms IgG subclass would accelerate AD research by expanding the choice of Abs available for histochemical analysis in AD studies.

neuroscience↗

bioRxiv2023

Coordinated changes in a cortical circuit sculpt effects of novelty on neural dynamics

Recent studies have found dramatic cell-type specific responses to stimulus novelty, highlighting the importance of analyzing the cortical circuitry at the cell-type specific level of granularity to understand brain function. Although initial work classified and characterized activity for each cell type, the specific alterations in cortical circuitry--particularly when multiple novelty effects interact--remain unclear. To address this gap, we employed a large-scale public dataset of electrophysiological recordings in the visual cortex of awake, behaving mice using Neuropixels probes and designed population network models to investigate the observed changes in neural dynamics in response to a combination of distinct forms of novelty. The model parameters were rigorously constrained by publicly available structural datasets, including multi-patch synaptic physiology and electron microscopy data. Our systematic optimization approach identified tens of thousands of model parameter sets that replicate the observed neural activity. Analysis of these solutions revealed generally weaker connections under novel stimuli, as well as a shift in the balance e between SST and VIP populations. Along with this, PV and SST populations experienced overall more excitatory influences compared to excitatory and VIP populations. Our results also highlight the role of VIP neurons in multiple aspects of visual stimulus processing and altering gain and saturation dynamics under novel conditions. In sum, our findings provide a systematic characterization of how the cortical circuit adapts to stimulus novelty by combining multiple rich public datasets.

neuroscience↗

bioRxiv2023

Low-CO2 inducible bestrophins in diatom thylakoid membranes sustain high photosynthetic efficacy at distant locations from the pyrenoid

Anion transporters are important to sustain a variety of physiological states in cells. Bestrophins are a family of Cl- and/or HCO3- transporters conserved in bacteria, animals, algae, and plants. Recently, bestrophin paralogs were found in the green alga Chlamydomonas reinhardtii as up- regulated components in low CO2 conditions that play an essential role in the CO2- concentrating mechanism (CCM). Bestrophin orthologs are also conserved in diatoms, a group of secondary endosymbiotic algae harboring red-type plastids, but their physiological functions are not known yet. Here, we characterized the subcellular localization and expression profile of bestrophins in the marine diatoms Phaeodactylum tricornutum (PtBST1-4) and Thalassiosira pseudonana (TpBST1 and 2). PtBST1 and PtBST2 were localized at the stromal thylakoid membrane outside of the pyrenoid, and PtBST3 was localized in the pyrenoid. Contrarily, TpBST1 and TpBST2 were both localized in the pyrenoid. These bestrophin proteins were accumulated in cells grown in atmospheric CO2 but not in 1% CO2-grown cells. To assess the physiological functions, we generated knock-out mutants for PtBST1 by genome editing. The lack of PtBST1 decreased affinity of photosynthesis for dissolved inorganic carbon closer to that of the cells grown in 1% CO2. Additionally, non-photochemical quenching was 1.5-2.0 times higher in the mutants than that of the wild type cells. These data suggests that HCO3- transport at the stroma thylakoid membranes by PtBST1 is a critical part of the CO2 evolving system of the pyrenoid in the fully induced CCM, and simultaneously that PtBST1 modulates photoprotection in response to CO2 availability in P. tricornutum. Significant statementMarine diatoms are responsible for nearly half of oceanic primary production, owing to the high-affinity photosynthesis for dissolved inorganic carbon which is supported by CO2- concentrating mechanism (CCM). This study uncovered that a bestrophin family protein at the stoma thylakoid membrane operates to import HCO3- to the thylakoid lumen and mobilizes it towards the CO2 evolving system at the pyrenoid-penetrating thylakoid in the diatom Phaeodactylum tricornutum. This HCO3- collecting system not only enhances the CCM but also down regulates the photoprotection capacity of photosystem II, presumably by affecting the thylakoid lumen acidification. This study experimentally demonstrates the molecular mechanism how diatoms optimize the use of CO2 and light energy, giving an insight into the reason of ecological successfulness of marine diatoms.

plant biology↗

bioRxiv2023

Injectable microcapillary network hydrogels engineered by liquid-liquid phase separation for stem cell transplantation

Injectable hydrogels are promising carriers for cell delivery in regenerative medicine. However, injectable hydrogels composed of crosslinked polymer networks are often non porous and prevent biological communication with host tissues through signals, nutrients, oxygen, and cells, thereby limiting graft survival and tissue integration. Here we report injectable hydrogels with liquid-liquid phase separation-induced microcapillary networks ({micro}CN) as stem cell-delivering scaffolds. The molecular modification of gelatin with hydrogen bonding moieties induced liquid-liquid phase separation when mixed with unmodified gelatin to form {micro}CN structures in the hydrogels. Through spatiotemporally controlled covalent crosslinking and dissolution processes, porous {micro}CN structures were formed in the hydrogels, which can enhance mass transport and cellular activity. The encapsulation of cells with injectable {micro}CN hydrogels improved cellular adhesion, spreading, migration, and proliferation. Transplantation of mesenchymal stem cells with injectable {micro}CN hydrogels enhanced graft survival and recovered hindlimb ischemia by enhancing material-tissue communication with biological signals and cells through {micro}CN. This facile approach may serve as an advanced scaffold for improving stem cell transplantation therapies in regenerative medicine.

bioengineering↗

bioRxiv2023

UV-induced feather color change reflects its porphyrin content

Pigmentary coloration is widespread in animals. Its evolutionary and ecological features are often attributed to the property of predominant pigments; therefore, most research has focused on predominant pigments such as carotenoids in carotenoid-based coloration. However, coloration results from predominant pigments and many other minority pigments, and the importance of the latter is overlooked. Here, we focused on porphyrin, an "uncommon" pigment found in bird feathers, and investigate its importance in the context of feather color changes in the barn swallow Hirundo rustica. We found that the "pheomelanin-based coloration" of the barn swallow faded after the irradiation of UV light, and this effect was particularly strong in the feathers of young swallows (nestlings and fledglings, here). We also found that it is not the predominant pigment, pheomelanin, but protoporphyrin IX pigment that showed the same pattern of depigmentation after the irradiation of UV light, particularly in the feathers of young swallows. In fact, the abovementioned age-dependent feather color change was statistically explained by the amount of porphyrin in the feathers. The current study demonstrates that a minority pigment, porphyrin, explains within-season dynamic color change, an ecological feature of feather coloration. The porphyrin-mediated rapid color change would benefit young birds, in which feather coloration affects the parental food allocation during a few weeks before independence, but not later. Future studies should not ignore these minor but essential pigments and their evolutionary and ecological functions. Significance statementPredominant pigments are assumed to determine animal coloration and its ecological features. It is then not surprising that the evolutionary and ecological features of animal coloration are often attributed to the chemical properties of predominant pigments. However, coloration results from predominant pigments and several other minority pigments. By irradiating UV light on reddish throat feathers of the barn swallow Hirundo rustica, we examined within-season dynamic color change in relation to a minority pigment, porphyrin, which has not previously been examined but is a candidate pigment for feather color change, because porphyrin can be easily photodegraded. We found that not the predominant pigment, pheomelanin, but porphyrin pigments explained the feather color change. Minor pigments and their chemical properties should not be dismissed to understand the ecological and evolutionary functions of animal coloration.

zoology↗

bioRxiv2023

Modulation of somatosensory signal transmission in the primate cuneate nucleus during voluntary hand movement

Successful extraction of tactile and kinematic information is crucial for appropriate motor actions in daily life. To achieve this objective, sensory signals should be effectively regulated during motor actions. This regulation is understood both empirically and conceptually, but it is not well known where and how it is implemented in the central nervous system. Here, we show that, during voluntary movement, sensory signals are already attenuated in the primate cuneate nucleus, an early processing site in the ascending lemniscus pathway. The degree of suppression was comparable with the one reported in the cortex, suggesting that psychological attenuation of somatosensation could be ascribed to the cuneate. The results also revealed that this sensory attenuation was of descending origin, suggesting that cortical sensory prediction signals could regulate cuneate sensory transmission for extracting meaningful, and attenuate unnecessary, signals for movement regulation. This recurrent sensory modulation mechanism between cortical and subcortical areas may generalize to other sensory modalities and cognitive processes.

neuroscience↗

bioRxiv2023

Effect of predicting familiar melodies on alpha power

The processing of music and language share similar characteristics. Previous studies indicated that the similarity between language and melody was observed in event-related potentials to the deviation of a word and tone, respectively. We focused on a language study that demonstrated strong suppression of the alpha power in the presence of easily predictable words. Motivated by the physiological similarity between language and music, this study hypothesized that predictable music might suppress the alpha power. We measured electroencephalogram (EEG) signals while a melody followed by silence was presented for a participant who imagined the melody during the silent part of the music. The participants scored the melodys familiarity to quantify the ease of prediction and imagination. We observed similarity to language processing. For familiar melodies, alpha power suppression was observed in the left frontal and left central regions. Further, we observed Bereitschaftspotential (a negative slope) in both familiar and unfamiliar conditions before the silent interval. Moreover, a network analysis revealed that information flow from the right sensory-motor cortex to the right auditory cortex in the beta band was stronger for familiar music than for unfamiliar music. Considering the previous findings that motor preparation and execution suppress the alpha power in the left frontal and left central regions, the alpha band suppression under music prediction suggests a motor interaction during music processing in the prediction of melodies.

neuroscience↗