PPP4C facilitates homologous recombination DNA repair by dephosphorylating PLK1 during early embryo development.

Mammalian early embryo cells have complex DNA repair mechanisms to maintain genomic integrity, and homologous recombination (HR) plays the main role in response to double-strand DNA breaks (DSBs) in these cells. Polo-like kinase 1 (PLK1) participates in the HR process and its overexpression has been shown to occur in a variety of human cancers. Nevertheless, the regulatory mechanism of PLK1 remains poorly understood, especially during the S and G2 phase. Here, we show that protein phosphatase 4 catalytic subunit (PPP4C) deletion causes severe female subfertility due to accumulation of DNA damage in oocytes and early embryos. PPP4C dephosphorylated PLK1 at the S137 site, negatively regulating its activity in the DSB response in early embryonic cells. Depletion of PPP4C induced sustained activity of PLK1 when cells exhibited DNA lesions that inhibited CHK2 and upregulated the activation of CDK1, resulting in inefficient loading of the essential HR factor RAD51. On the other hand, when inhibiting PLK1 in the S phase, DNA end resection was restricted. These results demonstrate that PPP4C orchestrates the switch between high-PLK1 and low-PLK1 periods, which couple the checkpoint to HR.

Upregulation of phosphodiesterase 7A leads to the downregulation of cAMP-PKA-CREB-BDNF signaling and neuroinflammation in the hippocampus and contributes to concurrent chronic pain and depression in two mouse models.

BACKGROUND: Phosphodiesterases (PDEs) are enzymes that catalyze the hydrolysis of cyclic adenosine monophosphate AMP (cAMP) and/or cyclic guanosine monophosphate (cGMP). PDE inhibitors can mitigate chronic pain and depression when these disorders occur individually; however, there is limited understanding of their role in concurrent chronic pain and depression. We aimed to evaluate the mechanisms of action of PDE using two mouse models of concurrent chronic pain and depression. METHODS: C57BL/6J mice were subjected to partial sciatic nerve ligation (PSNL) to induce chronic neuropathic pain or injected with complete Freund's adjuvant (CFA) to induce inflammatory pain, and both animals showed depression-like behavior. First, we determined the change in PDE expression in both animal models. Next, we determined the effect of PDE7 inhibitor BRL50481 or hippocampal PDE7A knockdown on PSNL- or CFA-induced chronic pain and depression-like behavior. We also investigated the role of cAMP-protein kinase A (PKA)-cAMP response element binding protein (CREB)-brain-derived neurotrophic factor (BDNF) signaling and neuroinflammation in the effect of PDE7A inhibition on PSNL- or CFA-induced chronic pain and depression-like behavior. RESULTS: This induction of chronic pain and depression in the two animal models upregulated hippocampal PDE7A. Oral administration of PDE7 inhibitor, BRL50481, or hippocampal PDE7A knockdown significantly reduced mechanical hypersensitivity and depression-like behavior. Hippocampal PDE7 inhibition reversed PSNL- or CFA-induced downregulation of cAMP and BDNF and the phosphorylation of PKA, CREB and p65. cAMP agonist forskolin, reversed these changes and caused milder behavioral symptoms of pain and depression. BRL50481 reversed neuroinflammation in the hippocampus in PSNL mice. CONCLUSIONS: Hippocampal PDE7A mediated concurrent chronic pain and depression in both mouse models by inhibiting cAMP-PKA-CREB-BDNF signaling Inhibiting PDE7A or activating cAMP-PKA-CREB-BDNF signaling are potential strategies to treat concurrent chronic pain and depression.

Characteristics of tunable aluminum-doped Ga2O3thin films and photodetectors.

Aluminum-doped Ga2O3(AGO) thin films were prepared by plasma-enhanced atomic layer deposition (PE-ALD). The growth mechanism, surface morphology, chemical composition, and optical properties of AGO films were systematically investigated. The bandgap of AGO films can be theoretically set between 4.65 and 6.8 eV. Based on typical AGO films, metal-semiconductor-metal photodetectors (PDs) were created, and their photoelectric response was examined. The preliminary results show that PE-ALD grown AGO films have high quality and tunable bandgap, and AGO PDs possess superior characterizations to undoped films. The AGO realized using PE-ALD is expected to be an important route for the development of a new generation of gallium oxide-based photodetectors into the deep-ultraviolet.

Two-dimensional molybdenum ditelluride waveguide-integrated near-infrared photodetector.

Low-cost, small-sized, and easy integrated high-performance photodetectors for photonics are still the bottleneck of photonic integrated circuits applications and have attracted increasing attention. The tunable narrow bandgap of two-dimensional (2D) layered molybdenum ditelluride (MoTe2) from ∼0.83 to ∼1.1 eV makes it one of the ideal candidates for near-infrared (NIR) photodetectors. Herein, we demonstrate an excellent waveguide-integrated NIR photodetector by transferring mechanically exfoliated 2D MoTe2onto a silicon nitride (Si3N4) waveguide. The photoconductive photodetector exhibits excellent responsivity (R), detectivity (D*), and external quantum efficiency at 1550 nm and 50 mV, which are 41.9 A W-1, 16.2 × 1010Jones, and 3360%, respectively. These optoelectronic performances are 10.2 times higher than those of the free-space device, revealing that the photoresponse of photodetectors can be enhanced due to the presence of waveguide. Moreover, the photodetector also exhibits competitive performances over a broad wavelength range from 800 to 1000 nm with a highRof 15.4 A W-1and a largeD* of 59.6 × 109Jones. Overall, these results provide an alternative and prospective strategy for high-performance on-chip broadband NIR photodetectors.

Progress on deep learning in genomics.

With the rapid growth of data driven by high-throughput sequencing technologies, genomics has entered an era characterized by big data, which presents significant challenges for traditional bioinformatics methods in handling complex data patterns. At this critical juncture of technological progress, deep learning-an advanced artificial intelligence technology-offers powerful capabilities for data analysis and pattern recognition, revitalizing genomic research. In this review, we focus on four major deep learning models: Convolutional Neural Network(CNN), Recurrent Neural Network(RNN), Long Short-Term Memory(LSTM), and Generative Adversarial Network(GAN). We outline their core principles and provide a comprehensive review of their applications in DNA, RNA, and protein research over the past five years. Additionally, we also explore the use of deep learning in livestock genomics, highlighting its potential benefits and challenges in genetic trait analysis, disease prevention, and genetic enhancement. By delivering a thorough analysis, we aim to enhance precision and efficiency in genomic research through deep learning and offer a framework for developing and applying livestock genomic strategies, thereby advancing precision livestock farming and genetic breeding technologies.

LRRC75A-AS1 delivered by M2 macrophage exosomes promotes cervical cancer progression via enhancing SIX1 expression.

We aimed to investigate potential roles of LRRC75A-AS1 delivered by M2 macrophage exosomes in inducing cervical cancer progression. We demonstrated LRRC75A-AS1 was highly expressed in exosomes from M2 macrophages which could be absorbed by Hela cells. M2 macrophage-derived exosomes promoted Hela cell proliferation, migration, invasion, and EMT process by delivering LRRC75A-AS1. LRRC75A-AS1 directly targeted and suppressed miR-429 in Hela cells. The regulation of cell functions by exosomes from LRRC75A-AS1-overexpressing M2 macrophages was abrogated by miR-429 mimics. miR-429 directly targeted and repressed SIX1 expression. SIX1 overexpression alleviated the modulation of cellular functions and STAT3/MMP-9 signaling by miR-429 mimics. Also, miR-429 overexpression or SIX1 silence repressed tumor formation and metastasis in nude mice, which was mitigated by exosomes from LRRC75A-AS1-overexpressing M2 macrophages. In conclusion, LRRC75A-AS1 delivered by M2 macrophage exosomes repressed miR-429 to elevate SIX1 expression and promote cervical cancer progression through activating the STAT3/MMP-9 axis.

An off-on fluorescent nanoprobe for L-cysteine sensing based on the FRET effect.

A self-assembled fluorescent nanosensor for the determination of L-cysteine (Cys) was constructed based on the mechanism of fluorescence resonance energy transfer (FRET). In this system, CdTe/ZnS QDs serve as the energy donor while AuNPs serve as the receptor, resulting in the occurrence of FRET with dramatic fluorescence quenching of the QDs (turn off). Once Cys is added, AuNPs can adsorb Cys, leading to the release of the QDs. The process would inhibit the FRET, which contributed to the recovery of fluorescence (turn on) and an off-on fluorescence aptasensor for Cys detection was constructed accordingly. The linear response range of the fluorescence sensor is from 0.8 to 50 µM, and the detection limit is 0.24 µM. The sensor demonstrates great sensitivity and selectivity to Cys. More importantly, the QD-based sensing platform was successfully used for the detection of Cys in milk samples with high precision and accuracy, indicating the potential of the probe in practical applications.

1D Chiral Enantiomer Lead-Free Perovskites Induced Chiralopical Activity and Photoelectric Response.

Chirality is a fascinating geometrical concept with widespread applications in biology, chemistry, and materials. Incorporating chirality into hybrid perovskite materials can induce novel physical properties (chiral optical activity, nonlinear optics, etc.). Hybrid lead-free or lead-substituted perovskite materials, as representatives of perovskites, have been widely used in fields such as photovoltaics, sensors, catalysis, and detectors. However, the successful introduction of chirality into hybrid lead-free perovskites, which can enable their potential applications in areas such as circularly polarized light photodetectors, memories, and spin transistors, remains a challenging research topic. Here, we synthesized two new chiral lead-free perovskites, [(R)-2-methylpiperazine][BiI5] and [(S)-2-methylpiperazine][BiI5]. The material possesses a perovskite structure with a one-dimensional (1D) arrangement, denoted as ABX5. This structure is composed of chiral cations, specifically methylpiperazine, and endless chains of [BiI3] along the a-axis. These chains are assembled from distorted coplanar [BiI5]2- octahedra. The testing results revealed that (R)-1 and (S)-1 have narrow band gaps (Eg-R = 2.016 eV, Eg-S = 1.964 eV), high photoelectric response, and long carrier lifetime [R = 4.94 µs (τ), S = 7.85 µs (τ)]. It is worth noting that 1D chiral lead-free perovskites (R)-1 and (S)-1, which are synthesized in this study with narrow band gaps, high photoelectric response, and long carrier lifetime, have the potential to serve as alternative materials for the perovskite layer in future iterations of lead-free perovskite solar cells. Moreover, this research will inspire the preparation of multifunctional, lead-free perovskites.

Machine learning-based identification of symptomatic carotid atherosclerotic plaques with dual-energy computed tomography angiography.

OBJECTIVE: This study aimed to develop and validate a machine learning model incorporating both dual-energy computed tomography (DECT) angiography quantitative parameters and clinically relevant risk factors for the identification of symptomatic carotid plaques to prevent acute cerebrovascular events. METHODS: The data of 180 patients with carotid atherosclerosis plaques were analysed from January 2017 to December 2021; 110 patients (64.03±9.58 years old, 20 women, 90 men) were allocated to the symptomatic group, and 70 patients (64.70±9.89 years old, 50 women, 20 men) were allocated to the asymptomatic group. Overall, five machine learning models using the XGBoost algorithm, based on different CT and clinical features, were developed in the training cohort. The performances of all five models were assessed in the testing cohort using receiver operating characteristic curves, accuracy, recall rate, and F1 score. RESULTS: The shapley additive explanation (SHAP) value ranking showed fat fraction (FF) as the highest among all CT and clinical features and normalised iodine density (NID) as the 10th. The model based on the top 10 features from the SHAP measurement showed optimal performance (area under the curve [AUC] .885, accuracy .833, recall rate .933, F1 score .861), compared with the other four models based on conventional CT features (AUC .588, accuracy .593, recall rate .767, F1 score .676), DECT features (AUC .685, accuracy .648, recall rate .667, F1 score .678), conventional CT and DECT features (AUC .819, accuracy .740, recall rate .867, F1 score .788), and all CT and clinical features (AUC .878, accuracy .833, recall rate .867, F1 score .852). CONCLUSION: FF and NID can serve as useful imaging markers of symptomatic carotid plaques. This tree-based machine learning model incorporating both DECT and clinical features could potentially comprise a non-invasive method for identification of symptomatic carotid plaques to guide clinical treatment strategies.

The benefit of contrast-enhanced ultrasound in biopsies for focal liver lesions: a retrospective study of 820 cases.

OBJECTIVE: This study compared the performance between ultrasound (US)- and contrast-enhanced US (CEUS)-guided liver biopsies and evaluated the benefit of CEUS in percutaneous biopsy for focal liver lesions (FLLs). METHODS: We performed a retrospective study of 820 patients with FLLs, who underwent percutaneous liver biopsy in our center between 2017 and 2019. The patients were divided into two groups based on whether US (n = 362) or CEUS (n = 458) used before a biopsy. The two groups were compared based on specimen adequacy for pathological diagnosis and diagnostic accuracy of liver biopsy. Stratification analysis was performed based on lesion and protocol characteristics to provide detailed information for selecting the imaging guidance for biopsy. RESULTS: Compared with the US group, the CEUS group yielded more acceptable samples (97.6% vs. 99.4%, p < 0.05) and improved diagnostic accuracy (92.6% vs. 96.4%, p < 0.05), and achieved better sensitivity (92.5% vs. 96.2%, p < 0.05) for liver biopsies, especially in FLLs ≥ 5 cm, heterogeneous hypoechoic FLLs, or FLLs with an obscure boundary. The CEUS group showed significantly higher accuracy compared with the US group pertaining to single-puncture biopsies (100% vs. 92.7%, p < 0.05) or biopsies with punctures ≤ 2 (97.6% vs. 94.3%, p < 0.05). CONCLUSION: CEUS achieved an enhanced success rate for sampling and diagnostic accuracy of liver biopsies, especially in FLLs ≥ 5 cm, heterogeneous hypoechoic FLLs, or FLLs with an obscure boundary. CEUS can be used to decrease the number of punctures needed, which might increase the safety of liver biopsy. KEY POINTS: • CEUS can help confirm an adequate biopsy site, increasing the sampling success rate and diagnostic accuracy of the liver biopsy. • CEUS can be used to decrease the number of punctures needed to improve the safety of liver biopsy. • It is recommended to use CEUS guidance for liver biopsies, especially with FLLs ≥ 5 cm, heterogeneous hypoechoic FLLs, or FLLs with an obscure boundary.

Combining conventional ultrasound and sonoelastography to predict axillary status after neoadjuvant chemotherapy for breast cancer.

OBJECTIVE: To determine the ability of conventional ultrasound (US) combined with shear wave elastography (SWE) to reveal axillary status after neoadjuvant chemotherapy (NAC) in breast cancer patients. METHODS: From September 2016 to December 2021, 201 patients with node-positive breast cancer who underwent NAC were enrolled in this prospective study. Conventional US features of axillary lymph nodes and SWE characteristics of breast lesions after NAC were analyzed. The diagnostic performances of US, SWE, and their combination were assessed using multivariate logistic regression and receiver operator characteristic curve (ROC) analyses. RESULTS: The area under the ROC curve (AUC) for the ability of conventional US features to determine axillary status after NAC was 0.82, with a sensitivity of 85.23%, a specificity of 67.39%, and an accuracy of 76.11%. Shear wave velocity (SWV) displayed moderate performance for predicting axilla status after NAC with SWVmean demonstrating an AUC of 0.85. Cortical thickness and shape of axillary nodes and SWVmean of breast tumors were independently associated with axillary nodal metastasis after NAC. Compared to conventional US, the combination of conventional US of axillary lymph nodes with SWE of breast lesions achieved a significantly higher AUC (0.90 vs 0.82, p < 0.01, Delong's test) with a sensitivity of 87.50%, improved specificity of 82.61% and accuracy of 85.00%. CONCLUSIONS: Breast SWE was independently associated with residual metastasis of axillary node after NAC in patients with initially diagnosed positive axilla. Combining SWE with conventional US showed good diagnostic performance for axillary node disease after NAC. KEY POINTS: • Breast SWE can serve as a supplement to axilla US for the evaluation of the axilla after NAC. • The combination of axilla US with breast SWE may be a promising method to facilitate less-invasive treatment in patients receiving NAC.

Self-assembled nanoplatforms with ZIF-8 as a framework for FRET-based glutathione sensing in biological samples.

A glutathione (GSH) optical sensor with high sensitivity and exceptional selectivity was established for the first time. Zeolitic imidazolate framework-8 (ZIF-8) as a model was used for the first time to entrap Mn2+:ZnS quantum dots (QDs) and a rhodamine B derivative (RBD) by self-assembly. Benefiting from the confinement effect of ZIF-8, the loaded QDs and RBD can be brought into close proximity for energy transfer to occur. In the presence of GSH, the fluorescence resonance energy transfer (FRET) process from the QDs to RBD can be initiated, rendering the fluorescent nanoprobe to exhibit a response to GSH. The fluorescence intensity of Mn2+:ZnS@ZIF-8@RBD decreased with an increase in the GSH concentration in the linear range of 5-120 µM and a detection limit of 1.5 µM. This finding leads to a method for the fluorescence detection of GSH with excellent selectivity over other reactive thiols. Moreover, because of its good accuracy and excellent recovery, the nanoplatform can be applied for GSH sensing in real human serum and urine samples. Hence, the developing probe may be extended to other optical sensing domains or drug carriers and has tremendous potential in the field of biomedicine.

Antifungal, Repellency, and Insecticidal Activities of Cymbopogon distans and Ruta graveolens Essential Oils and Their Main Chemical Constituents.

Essential oils produced by Cymbopogon distans and Ruta graveolens with a similar Chinese name could be explained as book fragrance in the Chinese idiom 'shu xiang men di', namely, a wealthy intellectual family according to ancient Chinese. Therefore, volatile oils from these two plants and their main compounds were tested to explore their antifungal, repellent, and insecticide actions. In this study, the essential olis (EO) of C. distans exhibited significant antifungal activity against Rhizopus stolonifera (97 %), Mucor racemosus (97 %), and Trichoderma viride (84 %); its main compounds exhibit interesting activity, such as methyleugenol (87 %) and elemicine (85 %) against T. viride and butyl hydroxytoluene against M. racemosus (90 %) and R. stolonifera (95 %). The EO of R. graveolens and other major chemical constituents showed weak inhibitory effects against other fungi (Aspergillus flavus and Fusarium oxysporum). Then, EO (C. distans and R. graveolens) and its main compounds exhibited obvious repellent activity (more than 85 %) at a concentration of 16 nL/cm2 , which was consistent with the repellency of the positive control (DEET). In terms of insecticidal activity, the mortality of C. distans volatile oil against R. padi (56.4 %) was lower than that of R. graveolens volatile oil (92.4 %), and all compounds showed weak lethal effects. These results provide a natural substance for controlling fungi and insects when storing books and that can be used as a biological pesticide for industrial production. Through our study, the book fragrance in the Chinese idiom 'shu xiang men di' was speculated to be the EO odor of C. distans.

First Report of Target Spot Caused by Rhizoctonia solani AG-6 in Tobacco in China.

Tobacco is an annual and solanaceous crop, which is widely produced in China. In July 2020, tobacco target spot was observed on 50% of tobacco plants in a 5-ha commercial field of Bijie (27.32° N, 105.29° E), Guizhou province, China. Typical symptoms firstly appeared on the old leaves as round watery spots. Then the spots became a diameter of 2 to 20 cm, with concentric ring lines and dead spots. Fifteen small pieces (5 × 5 mm) of leaf tissue were cut from the edge of the lesions, surface sterilized and placed on potato dextrose agar (PDA) medium amended with kanamycin (0.1 mg/ml). Isolate J136, one of five isolates with similar morphology, was selected for pathogen identification. The culture of the isolate on PDA was brown and exhibited radial mycelial growth after incubation at 28 oC in darkness for 5 days. Hyphae of the fungus were white at the beginning, turned light brown to brown at the later stages, and finally became thick and separated. Sclerotia were brown and produced on PDA after 25 days of incubation in the dark. These characteristics were similar to the colony characteristics of R. solani. The genomic DNA of Isolate J136 was extracted using the CTAB method. PCR analyses were conducted using the following primers specifically designed for the detection of individual AGs or subgroups of R. solani: AG-1 IA, IB and IC (Kuninaga 2003), AG-2-1, AG-2-2, IIIB, IV and LP (Carling et al. 2002), AG-3 PT (Misawa 2015), AG-4 HG-I and HG-II (Kuninaga 2003), and AGs-5-6 (Arakawa and Inagaki 2014). Among the 12 specific primer pairs, only AG-6-specific primers amplified a fragment of ca. 230 bp product, indicating that the tested strain belonged to R. solani AG-6. The sequence was deposited in GenBank with accession no. MZ379468. Using BLASTN search, the sequence of the gene was aligned with the voucher specimen, R. solani AG-6. A phylogenetic tree was constructed based on these sequences. After wards, Isolate J136 was tested for hyphal anastomosis reaction using the R. solani AG-6 standard strain according to the method described by Ogoshi (1987). The hyphal diameter at the point of anastomosis was reduced, with obvious anastomosis point, and the death of adjacent cells, indicating their anastomosis reactions (Anderson 1982). Thus, based on the morphological and genetic analyses, the fungus was identified as R. solani AG-6. To verify its pathogenicity, six plants (cv. Yunyan87) at the 5-to-6 leaf stage were inoculated with mycelial PDA plugs (5 mm in diameter). Leaves inoculated with PDA-only plugs served as the controls. Treated tobacco plants were maintained at a temperature range of 15 to 25 oC in a greenhouse with 85% relative humidity. After 5 days inoculation, typical symptoms were observed on the inoculated leaves, whereas no symptoms were observed on the control leaves. Koch's postulates were fulfilled by re-isolation of the pathogen from the diseased leaves. R. solani AG-2-2 is the only previously reported group of R. solani, which causes tobacco target spot in the field (Gonzalez et al. 2011). Therefore, to our knowledge, this is the first report of R. solani AG-6 causing target spot of tobacco in the field in China. Since considerable losses caused by the disease have frequently happened in this region, addition of this new group pathogen in the disease pool can be more problematic. Proper disease control strategies are in need to be developed to prevent further losses.

Three-Dimensional Metamaterial for Plasmon-Enhanced Raman Scattering at any Excitation Wavelengths from the Visible to Near-Infrared Range.

Plasmonic materials with highly confined electromagnetic fields at resonance wavelengths have been widely used to enhance Raman scattering signals. To achieve the maximum enhancement, the resonance peaks of the plasmonic materials should overlap with the excitation and emission wavelengths of target molecules, which is difficult for most of the plasmonic materials possessing a few narrow resonance peaks. Here, we report an ultrabroadband plasmonic metamaterial absorber (BPMA) that can absorb 99% of the incident light energy and excite plasmon resonance from the ultraviolet to near-infrared range (250-1900 nm), which allows us to observe efficient plasmon-enhanced Raman scattering (PERS) with any excitation sources. As demonstrated by the investigation on a self-assembled monolayer of the nonresonant molecule 4-mercaptobenzonitrile, the BPMA exhibits high PERS performance with a detection limit of down to 10-12 M under any excitation sources of three different lasers and excellent uniformity (∼5.51%) and reproducibility (∼5.50%), which corroborates the potential for high-throughput production with low cost and at a large scale. This work offers a novel platform for anti-interference PERS analysis in dynamic and complex environments.

Effects of Pretreatment with Bifidobacterium bifidum Using 16S Ribosomal RNA Gene Sequencing in a Mouse Model of Acute Colitis Induced by Dextran Sulfate Sodium.

BACKGROUND Bifidobacterium is a potentially effective and safe treatment for patients with inflammatory bowel disease (IBD), including ulcerative colitis and Crohn's disease. However, information on the influence of B. bifidum on gut microbial diversity of treated and pretreated IBD patients is limited. MATERIAL AND METHODS Our study investigated therapeutic and preventive effects of B. bifidum ATCC 29521 on C57BL/6 mice with dextran sulfate sodium (DSS)-induced acute colitis via 16S ribosomal ribonucleic acid (rRNA) gene sequencing. RESULTS Treatment and pretreatment of mice with B. bifidum ATCC 29521 significantly alleviated the severity of acute colitis on the basis of clinical and pathologic indicators. 16S rRNA gene sequencing showed that administration of B. bifidum shifted composition of the gut microbiome in mice with DSS-induced colitis in both treated and pretreated groups. Mice pretreated with B. bifidum ATCC 29521 for 21 days exhibited a significant increase in diversity of the gut microbiome. Principal coordinate analysis showed that gut microbiota structure was shaped by different treatments and time points. On the basis of linear discriminant analysis of effect size, the abundance of the genus Escherichia-Shigella, belonging to the family Enterobacteriaceae, was reduced in the B. bifidum-treated group, indicating that pathogens were inhibited by the B. bifidum treatment. Furthermore, the genera Intestinimonas and Bacteroides were significantly associated with the B. bifidum-pretreated group. CONCLUSIONS 16S rRNA gene sequencing showed that pretreatment with B. bifidum ATCC 29521 reduced intestinal inflammation and altered the gut microbiota to favor the genera Intestinimonas and Bacteroides.

First Report of Leaf spot Caused by Xylaria arbuscula on Flue-cured Tobacco in China.

Flue-cured tobacco (Nicotiana tabacum L.) is a leafy, annual, solanaceous plant grown commercially for its leaves in China. Around 70% of tobacco production in China occurs in southwest China. In summer of 2019, leaf spot symptoms were observed on ten to twenty percent of tobacco plants in a 2 ha commercial field of Bijie (27.32° N, 105.29° E), Guizhou province, China. The leaf spots were white with dark-brown in edges, irregularly round and oval, and diseased tissue dropped out leaving the leaves ragged in appearance (Fig. 1A, 1B). One diseased leaf from each of five plants was sampled. From five leaves, a total of 15 small (5 mm × 5 mm) pieces of leaf tissue were cut from the edge of the lesions after surface sterilization and placed on potato dextrose agar (PDA) medium. Five fungal colonies that were similar in appearance were isolated and one was purified, BEZ22, was selected arbitrarily for identification. Mycelia of the pathogen was initally white and dense, and then black carbonized mycelia appeared from the center of the colony 7 days' after incubation. Mycelia was white, sparse and radiated when incubated on OA (oatmeal agar) (Fig. 1E, 1F, 1G, 1H). Genomic DNA of the isolate was extracted. The internal transcribed spacers (ITS) with primers ITS1/ITS4 (White et al. 1990), actin (ACT) gene with primers ACT-512F/ACT-738R (Hsieh et al. 2005), beta-tubulin (TUB2) with primers T1/T22 (O'Donnell & Cigelnik 1997) and RNA polymerase II second largest subunit gene (RPB2) with primers fRPB2-5F/ fRPB2-7cR (Liu et al. 1999) were amplified and sequenced, respectively. The generated sequences were deposited in GenBank with accession numbers MT804353 (ITS), MT809582 (ACT), MT799790 (TUB2) and MT799789 (RPB2). Using BLASTN searches, the sequences of each gene above were aligned with the voucher specimum, Xylaria arbuscula 89041211. The number of nucleotides that were similar for ITS (GU300090) was 550/551 (99%); for ACT (GQ421286), 266/266 bp (100%); for TUB2 (GQ478226), 1501/1501 bp (100%); and for RPB2 (GQ844805), 1135/1135 bp (100%), respectively (Fig. 2). A phylogenetic tree was constructed based on these four sequences with a final alignment of 3456 characters (ITS 551, ACT 266, TUB2 1501 and RPB2 1138). Thus, based on morphological and phylogenetic analyses, the isolate BEZ22 was identified as Xylaria arbuscula. To verify pathogenicity, six tobacco plants at seedling stage (5-6 leaves) without visible disease were inoculated using mycelial plugs (5 mm in diameter). Leaves inoculated with PDA only plugs served as controls. After inoculation, all tobacco plants were maintained in a greenhouse with 85% relative humidity at 25 oC under a 12/12 h light/dark cycle. Five days after inoculation, typical early symptoms were observed on the inoculated leaves, and not on the control leaves. Koch's postulates were fulfilled by re-isolation of the pathogen from diseased leaves. Xylaria arbuscula has also been reported as a pathogen of Macadamia in Hawaii (Wenhsiung et al. 2009) and sugarcane in Indonesia (Maryono et al. 2020). However, to our best knowledge, this is the first report of X. arbuscula causing leaf spot on tobacco in China. This leaf spot has the potential to cause serious damage to tobacco in this region that could result in reduced production, consequently disease management of this pathogen should be considered.

Type I H+-pyrophosphatase regulates the vacuolar storage of sucrose in citrus fruit.

The aim of this work was to evaluate the general role of the vacuolar pyrophosphatase proton pump (V-PPase) in sucrose accumulation in citrus species. First, three citrus V-PPase genes, designated CsVPP-1, CsVPP-2, and CsVPP-4, were identified in the citrus genome. CsVPP-1 and CsVPP-2 belonging to citrus type I V-PPase genes are targeted to the tonoplast, and CsVPP-4 belonging to citrus type II V-PPase genes is located in the Golgi bodies. Moreover, there was a significantly positive correlation between transcript levels of type I V-PPase genes and sucrose, rather than hexose, content in fruits of seven citrus cultivars. Drought and abscisic acid treatments significantly induced the CsVPP-1 and CsVPP-2 transcript levels, as well as the sucrose content. The overexpression of type I V-PPase genes significantly increased PPase activity, decreased pyrophosphate contents, and increased sucrose contents, whereas V-PPase inhibition produced the opposite effect in both citrus fruits and leaves. Furthermore, altering the expression levels of type I V-PPase genes significantly influenced the transcript levels of sucrose transporter genes. Taken together, this study demonstrated that CsVPP-1 and CsVPP-2 play key roles in sucrose storage in the vacuole by regulating pyrophosphate homeostasis, ultimately the sucrose biosynthesis and transcript levels of sucrose transport genes, providing a novel lead for engineering or breeding modified taste in citrus and other fruits.

pH-Dependent Slipping and Exfoliation of Layered Covalent Organic Framework.

Layered/two-dimensional covalent organic frameworks (2D COF) are crystalline porous materials composed of light elements linked by strong covalent bonds. Interlayer force is one of the main factors directing the formation of a stacked layer structure, which plays a vital role in the stability, crystallinity, and porosity of layered COFs. The as-developed new way to modulate the interlayer force of imine-linked 2D TAPB-PDA-COF (TAPB = 1,3,5-tris(4-aminophenyl)benzene, PDA = terephthaldehyde) by only adjusting the pH of the solution. At alkaline and neutral pH, the pore size of the COF decreases from 34 Šdue to the turbostratic effect. Under highly acidic conditions (pH 1), TAPB-PDA-COF shows a faster and stronger turbostratic effect, thus causing the 2D structure to exfoliate. This yields bulk quantities of an exfoliated few/single-layer 2D COF, which was well dispersed and displayed a clear Tyndall effect (TE). Furthermore, nanopipette-based electrochemical testing also confirms the slipping of layers with increase towards acidic pH. A model of pH-dependent layer slipping of TAPB-PDA-COF was proposed. This controllable pH-dependent change in the layer structure may open a new door for potential applications in controlled gas adsorption/desorption and drug loading/releasing.

Assessment of sugar and sugar accumulation-related gene expression profiles reveal new insight into the formation of low sugar accumulation trait in a sweet orange (Citrus sinensis) bud mutant.

The accumulation of soluble sugars in fleshy fruits largely determines their sweetness or taste. A spontaneous sweet orange mutant 'Hong Anliu' (HAL, Citrus sinensis) accumulates low soluble sugar content in fruit juice sacs than its wild type, 'Anliu' (AL) orange; however, the cause of reduced sugar content in 'HAL' fruit remains unclear. In this study, sugar content and expression profiles of genes involved in sugar metabolism and transport were compared between 'HAL' and 'AL' fruit juice sacs. In both cultivars, fructose and glucose displayed the increasing trends with significantly lower contents in 'HAL' than 'AL' after 160 DAF; moreover, sucrose had a declining trend in 'HAL' and increasing trend in 'AL' with fruit development. On the other hand, transcript levels of VINV, CWINV1, CWINV2, SUS4, SUS5, SPS1, SPS2, VPP-1, VPP-2, and some sugar transporter genes were significantly decreased in 'HAL' compared with 'AL' after 100 DAF or 160 DAF. Interestingly, the transcript levels of SPS2 and SUT2 exhibited a similar trend as it was found for sucrose content in both cultivars. These results suggested that the low sugar accumulation in 'HAL' fruit JS is accompanied by the reduced sink strength, sucrose-synthesis ability, and vacuolar storage ability compared with 'AL'; reduction of CWINVs, VINV, SPS2, SUT2, VPP-1, and VPP-2 transcript levels possibly plays a key role in the low storage of soluble sugars in the vacuoles of mutant juice sacs.