A single photoreceptor splits perception and entrainment by cotransmission.

Vision enables both image-forming perception, driven by a contrast-based pathway, and unconscious non-image-forming circadian photoentrainment, driven by an irradiance-based pathway1,2. Although two distinct photoreceptor populations are specialized for each visual task3-6, image-forming photoreceptors can additionally contribute to photoentrainment of the circadian clock in different species7-15. However, it is unknown how the image-forming photoreceptor pathway can functionally implement the segregation of irradiance signals required for circadian photoentrainment from contrast signals required for image perception. Here we report that the Drosophila R8 photoreceptor separates image-forming and irradiance signals by co-transmitting two neurotransmitters, histamine and acetylcholine. This segregation is further established postsynaptically by histamine-receptor-expressing unicolumnar retinotopic neurons and acetylcholine-receptor-expressing multicolumnar integration neurons. The acetylcholine transmission from R8 photoreceptors is sustained by an autocrine negative feedback of the cotransmitted histamine during the light phase of light-dark cycles. At the behavioural level, elimination of histamine and acetylcholine transmission impairs R8-driven motion detection and circadian photoentrainment, respectively. Thus, a single type of photoreceptor can achieve the dichotomy of visual perception and circadian photoentrainment as early as the first visual synapses, revealing a simple yet robust mechanism to segregate and translate distinct sensory features into different animal behaviours.

Molecular Mechanisms of the Melatonin Receptor Pathway Linking Circadian Rhythm to Type 2 Diabetes Mellitus.

Night-shift work and sleep disorders are associated with type 2 diabetes (T2DM), and circadian rhythm disruption is intrinsically involved. Studies have identified several signaling pathways that separately link two melatonin receptors (MT1 and MT2) to insulin secretion and T2DM occurrence, but a comprehensive explanation of the molecular mechanism to elucidate the association between these receptors to T2DM, reasonably and precisely, has been lacking. This review thoroughly explicates the signaling system, which consists of four important pathways, linking melatonin receptors MT1 or MT2 to insulin secretion. Then, the association of the circadian rhythm with MTNR1B transcription is extensively expounded. Finally, a concrete molecular and evolutionary mechanism underlying the macroscopic association between the circadian rhythm and T2DM is established. This review provides new insights into the pathology, treatment, and prevention of T2DM.

GCmapCrys: Integrating graph attention network with predicted contact map for multi-stage protein crystallization propensity prediction.

X-ray crystallography is the major approach for atomic-level protein structure determination. Since not all proteins can be easily crystallized, accurate prediction of protein crystallization propensity is critical to guiding the experimental design and improving the success rate of X-ray crystallography experiments. In this work, we proposed a new deep learning pipeline, GCmapCrys, for multi-stage crystallization propensity prediction through integrating graph attention network with predicted protein contact map. Experimental results on 1548 proteins with known crystallization records demonstrated that GCmapCrys increased the value of Matthew's correlation coefficient by 37.0% in average compared to state-of-the-art protein crystallization propensity predictors. Detailed analyses show that the major advantages of GCmapCrys lie in the efficiency of the graph attention network with predicted contact map, which effectively associates the residue-interaction knowledge with crystallization pattern. Meanwhile, the designed four sequence-based features can be complementary to further enhance crystallization propensity proprediction.

Unveiling the effect of water on photoinduced electron transfer by crystallographic study.

A series of proof-of-concept models with different degrees of hydration in the same donor-acceptor system were obtained through a functional motif-oriented structural design and screening strategy. The effect of water molecules on photoinduced electron transfer was explored from a crystallographic perspective for the first time. The reasons for the structural differences caused by different degrees of hydration were also discussed.

Photochromic Semiconductors: Bottom-Up Strategy to Construct Type II-Stacking Viologen π-Aggregates.

Semiconductor conductivities depend largely on the crystal structures and the associated electronic structures. If the electronic structures can be switched reversibly in the same crystal structure, then a drastic conductivity change may be controllable. The effect of electron transfer (ET) on semiconductor conductivity remained elusive so far. In this work, a series of two pillared inorganicorganic hybrid photochromic semiconductors (PSCs), [(CQ)Pb3X6(H2O)]·2H2O [X = Cl (1) and Br (2), CQ = N-4,4'-bipyridiniopropionate (viologen)], with II-stacking viologen π-aggregates, are constructed by a bottom-up self-assembly strategy through inorganic skeleton-directed intercalation and intermolecular noncovalent interaction. The conductivities are abnormally "invariant" after photoinduced ET, breaking the convention that the generation of radicals favors conductivity. The abnormally "invariant" conductivities are mainly derived from approximate electronic couplings before and after ET between II-stacking viologen π-aggregates.

Learning Protein Embedding to Improve Protein Fold Recognition Using Deep Metric Learning.

Protein fold recognition refers to predicting the most likely fold type of the query protein and is a critical step of protein structure and function prediction. With the popularity of deep learning in bioinformatics, protein fold recognition has obtained impressive progress. In this study, to extract the fold-specific feature to improve protein fold recognition, we proposed a unified deep metric learning framework based on a joint loss function, termed NPCFold. In addition, we also proposed an integrated machine learning model based on the similarity of proteins in various properties, termed NPCFoldpro. Benchmark experiments show both NPCFold and NPCFoldpro outperform existing protein fold recognition methods at the fold level, indicating that our proposed strategies of fusing loss functions and fusing features could improve the fold recognition level.

UV-vis/X-ray/thermo-induced synthesis and UV-SWIR photoresponsive property of a mixed-valence viologen molybdate semiconductor.

A new design strategy through the synergy of Mo(vi)-Mo(v) intervalence charge transfer and π(radical)-π(radical/cation) interactions is proposed to obtain semiconductors with photoresponsive ranges covering the whole UV-SWIR (ultraviolet-shortwave near-infrared; ca. 250-3000 nm) region. With this strategy, a viologen-based molybdate semiconductor with a UV-SWIR photoresponsive range was obtained through UV/X-ray irradiation or thermal annealing. The thermally annealed semiconductor has the highest conversion and the best photocurrent response in the range of 355-2400 nm.

Glycomyces xinjiangensis sp. nov., a novel actinomycete isolated from a hypersaline habitat.

A novel actinomycete strain, designated XHU 5301T, was isolated from a hypersaline habitat, China. The strain was aerobic, Gram-stain positive and the optimum NaCl concentration for growth was 7-9% (w/v). Phylogenetic analysis based on an almost-complete 16S rRNA gene sequence of strain XHU 5301T showed that the organism was most closely related to Glycomyces halotolerans TRM 40137T (96.0%). The whole-cell sugar pattern consisted of glucose and galactose. The predominant menaquinone was MK-10(H4), MK-10(H2), and MK-9(H4). The major fatty acids were anteiso-C15: 0, iso-C15: 0, iso-C16: 0, and methyl-C19: 0. The polar lipids consist of diphosphatidylglycerol, phosphatidylglycerol, and one unknown phospholipid. The G+C content of the genomic DNA was 72.5 mol %. The novel species Glycomyces xinjiangensis sp. nov. was proposed, with strain XHU 5301T (=CCTCC AA 2016043T =KCTC 39689T) as the type strain of Glycomyces xinjiangensis.

Glycomyces lacisalsi sp. nov., an actinomycete isolated from a hypersaline habitat.

A novel actinomycete strain, designated XHU 5089T, was isolated from a hypersaline habitat in China. The strain was aerobic, Gram-stain-positive and the optimum NaCl concentration for growth was 1-3 % (w/v). Phylogenetic analysis based on the almost-complete 16S rRNA gene sequence of strain XHU 5089T showed that the organism was related most closely to Glycomyces albusTRM 49136T (97.7 % similarity). However, it had a relatively low mean DNA-DNA relatedness value with G. albusTRM 49136T (18.9±5.8 %). The whole-cell sugar pattern consisted of glucose and galactose. The predominant menaquinones were MK-10(H4) and MK-9(H4). The major fatty acids were anteiso-C15 : 0, iso-C16 : 0, iso-C16 : 1 and anteiso-C17 : 0. The polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol, two unidentified glycolipids and two unknown phospholipids. The G+C content of the genomic DNA was 68.6 mol%. A novel species, Glycomyces lacisalsi sp. nov., is proposed, with XHU 5089T (=CCTCC AA 2015034T=KCTC 39688T) as the type strain.