NanoDeep: a deep learning framework for nanopore adaptive sampling on microbial sequencing.

Nanopore sequencers can enrich or deplete the targeted DNA molecules in a library by reversing the voltage across individual nanopores. However, it requires substantial computational resources to achieve rapid operations in parallel at read-time sequencing. We present a deep learning framework, NanoDeep, to overcome these limitations by incorporating convolutional neural network and squeeze and excitation. We first showed that the raw squiggle derived from native DNA sequences determines the origin of microbial and human genomes. Then, we demonstrated that NanoDeep successfully classified bacterial reads from the pooled library with human sequence and showed enrichment for bacterial sequence compared with routine nanopore sequencing setting. Further, we showed that NanoDeep improves the sequencing efficiency and preserves the fidelity of bacterial genomes in the mock sample. In addition, NanoDeep performs well in the enrichment of metagenome sequences of gut samples, showing its potential applications in the enrichment of unknown microbiota. Our toolkit is available at https://github.com/lysovosyl/NanoDeep.

BLMP-1 promotes developmental cell death in C. elegans by timely repression of ced-9 transcription.

Programmed cell death (PCD) is a common cell fate in metazoan development. PCD effectors are extensively studied, but how they are temporally regulated is less understood. Here, we report a mechanism controlling tail-spike cell death onset during Caenorhabditis elegans development. We show that the zinc-finger transcription factor BLMP-1, which controls larval development timing, also regulates embryonic tail-spike cell death initiation. BLMP-1 functions upstream of CED-9 and in parallel to DRE-1, another CED-9 and tail-spike cell death regulator. BLMP-1 expression is detected in the tail-spike cell shortly after the cell is born, and blmp-1 mutations promote ced-9-dependent tail-spike cell survival. BLMP-1 binds ced-9 gene regulatory sequences, and inhibits ced-9 transcription just before cell-death onset. BLMP-1 and DRE-1 function together to regulate developmental timing, and their mammalian homologs regulate B-lymphocyte fate. Our results, therefore, identify roles for developmental timing genes in cell-death initiation, and suggest conservation of these functions.

Urchin-Like Mesoporous TiN Hollow Sphere Enabling Promoted Electrochemical Kinetics of Bromine-Based Flow Batteries.

Bromine-based flow batteries (BFB) have always suffered from poor kinetics due to the sluggish Br3 -/Br- redox, hindering their practical applications. Developing cathode materials with high catalytic activity is critical to address this challenge. Herein, the in-depth investigation for the free energy of the bromine redox electrode is conducted initially through DFT calculations, establishing the posterior desorption during oxidation as the rate-determining step. An urchin-like titanium nitride hollow sphere (TNHS) composite is designed and synthesized as the catalyst for bromine redox. The large difference in Br- and Br3 - adsorption capability of TNHS promotes rapid desorption of generated Br3 - during the oxidation process, liberating active sites timely to enable smooth ongoing reactions. Besides, the urchin-like microporous/mesoporous structure of TNHS provides abundant active surface for bromine redox reactions, and ample cavities for the bromine accommodation. The inherently high conductivity of TNHS enables facile electron transfer through multiple channels. Consequently, zinc-bromide flow batteries with TNHS catalyst exhibit significantly enhanced kinetics, stably operating at 80 mA cm-2 with 82.78% energy efficiency. Overall, this study offers a solving strategy and catalyst design approach to the sluggish kinetics that has plagued bromine-based flow batteries.

Bispecific Nanobody-Aptamer Conjugates for Enhanced Cancer Therapy in Solid Tumors.

Bispecific antibodies possess exceptional potential as therapeutic agents due to their capacity to bind to two different antigens simultaneously. However, challenges pertain to unsatisfactory stability, manufacturing complexity, and limited tumor penetration hinder their broad applicability. In this study, a versatile technology is presented for the rapid generation of bispecific nanobody-aptamer conjugates with efficient tumor penetration. The approach utilizes microbial transglutaminase (MTGase) and click chemistry to achieve site-specific conjugation of nanobodies and aptamers, which are termed nanotamers. The nanotamers recognize and bind to two types of molecular targets expressed on cancer cells. As a prototype, a bispecific nanotamer is developed that binds both clusters of differentiation 47 (CD47) and mesenchymal epithelial transition receptor (Met) expressed on the tumor cell membrane. This CD47-Met nanotamer demonstrates high affinity and specificity toward tumor cells expressing both targets, exhibits improved receptor functional inhibition through a strong steric hindrance effect. Moreover, its capacity for deep tumor penetration greatly enhances the impact of conventional chemotherapy on antitumor efficacy. The as-developed nanotamer synthesis approach shows promise to customize bispecific molecular probes targeting different cancer types and different therapeutic goals.

Alterations of the bile microbiome is associated with progression-free survival in pancreatic ductal adenocarcinoma patients.

BACKGROUND: Patients with pancreatic ductal adenocarcinoma (PDAC) display an altered oral, gastrointestinal, and intra-pancreatic microbiome compared to healthy individuals. However, knowledge regarding the bile microbiome and its potential impact on progression-free survival in PDACs remains limited. METHODS: Patients with PDAC (n = 45), including 20 matched pairs before and after surgery, and benign controls (n = 16) were included prospectively. The characteristics of the microbiomes of the total 81 bile were revealed by 16  S-rRNA gene sequencing. PDAC patients were divided into distinct groups based on tumor marker levels, disease staging, before and after surgery, as well as progression free survival (PFS) for further analysis. Disease diagnostic model was formulated utilizing the random forest algorithm. RESULTS: PDAC patients harbor a unique and diverse bile microbiome (PCoA, weighted Unifrac, p = 0.038), and the increasing microbial diversity is correlated with dysbiosis according to key microbes and microbial functions. Aliihoeflea emerged as the genus displaying the most significant alteration among two groups (p < 0.01). Significant differences were found in beta diversity of the bile microbiome between long-term PFS and short-term PFS groups (PCoA, weighted Unifrac, p = 0.005). Bacillota and Actinomycetota were identified as altered phylum between two groups associated with progression-free survival in all PDAC patients. Additionally, we identified three biomarkers as the most suitable set for the random forest model, which indicated a significantly elevated likelihood of disease occurrence in the PDAC group (p < 0.0001). The area under the receiver operating characteristic (ROC) curve reached 80.8% with a 95% confidence interval ranging from 55.0 to 100%. Due to the scarcity of bile samples, we were unable to conduct further external verification. CONCLUSION: PDAC is characterized by an altered microbiome of bile ducts. Biliary dysbiosis is linked with progression-free survival in all PDACs. This study revealed the alteration of the bile microbiome in PDACs and successfully developed a diagnostic model for PDAC.

One-Step Formation of Pickering Double Emulsion Costabilized by Hydrophobic Silica Nanoparticles and Sodium Alginate.

Pickering double emulsions exhibit higher stability and biocompatibility compared with surfactant-stabilized double emulsions. However, tailored synthesis of particle stabilizers with appropriate wettability is time consuming and complicated and usually limits their large-scale adoption. Using binary stabilizers may be a simple and scalable strategy for Pickering double emulsion formation. Herein, commercially available hydrophobic silica nanoparticles (SNPs) and sodium alginate (SA) as binary stabilizers are used to prepare O/W/O Pickering double emulsions in one-step emulsification. The influence of system composition on double emulsion preparation is identified by optical microscopy, confocal laser scanning microscopy, and interfacial tension and water contact angle analyses. The formation of the O/W/O Pickering double emulsion depends critically on the aqueous phase viscosity and occurrence of emulsion inversion. Both hydrophobic SNPs and SA adsorb at the droplet surface to provide a steric barrier, while SA also reduces interfacial tension and increases aqueous phase viscosity, giving double emulsion long-term stability. Their microstructure and stability are controlled by adjusting the SA concentration, water-oil volume ratio, concentration and wettability of the particle stabilizer, and oil type. As a demonstration, the middle layer of the as-prepared O/W/O Pickering double emulsions can be cross-linked in situ with calcium ions to produce calcium alginate porous microspheres. We believe that our strategy for double emulsion formation holds great potential for practical applications in food, cosmetics, or pharmaceuticals.

C. elegans BLMP-1 controls apical epidermal cell morphology by repressing expression of mannosyltransferase bus-8 and molting signal mlt-8.

Skin epidermis secretes apical extracellular matrix (aECM) as a protective barrier from the external environment. The aECM is highly dynamic and constantly undergoes remodeling during animal development. How aECM dynamics is temporally regulated during development, and whether and how its mis-regulation may impact epidermal cell morphology or function remains to be fully elucidated. Here, we report that the conserved Zn-finger transcription factor BLMP-1/Blimp1, which regulates epidermal development in C. elegans, controls apical cell shape of the epidermis by downregulation of aECM remodeling. Loss of blmp-1 causes upregulation of genes essential for molting, including bus-8 and mlt-8, in adult, leading to an abnormal shape in the apical region of adult epidermal cells. The apical epidermal morphological defect is suppressed by reduction of bus-8 or mlt-8. BUS-8 is a key mannosyltransferase, which functions in glycosylation of N-linked glycoproteins; MLT-8 has a ganglioside GM2 lipid-binding domain and is implicated in signaling during molting, a process where the old cuticle is shed and synthesized anew. Overexpression of bus-8 or mlt-8 induces an apical epidermal cell defect as observed in blmp-1 mutants. MLT-8::GFP fusion protein is localized to lysosomes and secreted to aECM. BUS-8 is important for MLT-8 stability and lysosomal targeting, which may be regulated by BUS-8-mediated glycosylation of MLT-8 and function as a molting signaling cue in aECM remodeling. We propose that BLMP-1 represses MLT-8 expression and glycosylation in the epidermis to prevent inappropriate aECM remodeling, which is essential for maintenance of apical epidermal cell morphology during larva-to-adult transition.

Thickness-dependent loss-induced failure of an ideal ENZ-enhanced optical response in planar ultrathin transparent conducting oxide films.

Ultrathin planar transparent conducting oxide (TCO) films are commonly used to enhance the optical response of epsilon-near-zero (ENZ) devices; however, our results suggest that thickness-dependent loss renders them ineffective. Here, we investigated the thickness-dependent loss of indium tin oxide (ITO) films and their effect on the ENZ-enhanced optical responses of ITO and ITO/SiO2 multilayer stacks. The experimental and computational results show that the optical loss of ITO films increases from 0.47 to 0.70 as the thickness decreases from 235 to 52 nm, which results in a reduction of 60% and 45% in the maximum field enhancement factor of a 52-nm monolayer ITO and 4-layer ITO/SiO2 multilayer stack, respectively. The experimental results show that the ENZ-enhanced nonlinear absorption coefficient of the 52-nm single-layer ITO film is -1.6 × 103 cm GW-1, which is 81% lower than that of the 235-nm ITO film (-8.6 × 103 cm GW-1), indicating that the thickness-dependent loss makes the ultrathin TCO films unable to obtain greater nonlinear responses. In addition, the increased loss reduces the cascading Berreman transmission valley intensity of the 4-layer ITO/SiO2 multilayer stack, resulting in a 42% reduction in the ENZ-enhanced nonlinear absorption coefficient compared to the 235-nm ITO film and a faster hot electron relaxation time. Our results suggest that the thickness and loss trade-off is an intrinsic property of TCO films and that the low-loss ultrathin TCO films are the key to the robust design and fabrication of novel ENZ devices based on flat ultrathin TCO films.

Lab-on-fiber: laser-induced micro-cavity for a relative humidity measurement.

The lab-on-fiber design philosophy is the foundation for creating high-performance integrated fiber sensors. Hence, this Letter proposes an ultra-compact Fabry-Perot interferometer (FPI) based on a laser-induced micro-cavity (LIMC-FPI) on a fiber end for measuring relative humidity. To our knowledge, this novel approach, named the fiber-end photopolymerization (FEP) technique, is applied to create a micro-cavity. Specifically, a pair of humidity-sensitive polymer pillars and a resin end cap obtained by FEP are integrated to generate the cavity. As the ambient humidity changes, the pillars lengthen or shorten, resulting in the spectral evolution of the LIMC-FPI. A typical humidity sensitivity of 0.18 nm/%RH is obtained experimentally. For monitoring the human breathing process, the LIMC-FPI is responsive in the breathing frequency range of 0.2 to 0.5 Hz, allowing a response and recovery time of less than 0.388 s and 1.171 s, respectively. This work introduces a fresh and cost-effective approach for developing lab-on-fiber concept-based sensors.

Cancer-associated fibroblasts-derived exosomes from chemoresistant patients regulate cisplatin resistance and angiogenesis by delivering VEGFA in colorectal cancer.

The purpose of this study was to investigate the effect of chemoresistant cancer-associated fibroblasts (R-CAFs) against cisplatin (DDP) on colorectal cancer (CRC) progression. First, clinical tissue samples of chemoresistant or chemosensitive CRC patients were collected to isolate R-CAFs or chemosensitive CAFs (S-CAFs), respectively. HT29 cells or HUVECs were co-cultured with R-CAFs by transwell device. Then the proliferation and apoptosis of HT29 cells were detected with Cell Counting Kit-8 (CCK-8) and flow cytometry. Transwell assay and tube formation assay was used to detect the migration and angiogenesis of HUVECs. In addition, a colorectal cancer transplantation model was established subcutaneously in nude mice by injecting stably transfected HT29 cells and exosomes from different CAF groups, and then the tumor volume and weight were measured and recorded. Hematoxylin and eosin staining, immunohistochemistry, and terminal deoxynucleotidyl transferase dUTP Nick-End Labeling (TUNEL) staining were performed to characterize the histopathological characteristics and apoptosis level of tumor tissues, respectively. S-CAFs and R-CAFs were isolated successfully. HT29 cell co-culture with R-CAFs significantly affected the proliferation and apoptosis of HT29 cells. Exosomes derived from R-CAFs (R-CAFs-Exo) were delivered to HT29 cells, which could induce viability, suppress apoptosis and accelerate the angiogenesis of CRC. In addition, VEGFA was highly expressed in R-CAFs-Exo, which might indicate that R-CAFs could transmit VEGFA through exosomes. Overexpressed VEGFA in R-CAFs apparently regulates the viability, apoptosis, DDP resistance, and angiogenesis of CRC. In-vivo experiments confirmed that R-CAFs-Exo promoted the progression of CRC and DDP resistance by delivering VEGFA . R-CAFs-derived exosomes promote the viability, apoptosis, DDP resistance, and angiogenesis of CRC by delivering VEGFA .

Dual-responsive colloidosome-like microgels as the building blocks for phase inversion of Pickering emulsions.

The intelligent regulation of microgel-stabilized Pickering emulsions with multi-responsiveness is presently constrained to the processes of emulsification and destabilization. However, the expansion of multi-control over Pickering emulsions to involve phase inversion and the investigation of the accompanying processes and mechanisms present a great challenge. In this study, a microgel with dual responsiveness to both pH and temperature was synthesized using an emulsion template. The resulting microgel exhibited a robust colloidosome-like structure, distinguished by the presence of monolayer-adsorbed silica nanoparticles. The regulation of the packing of surface-covered silica nanoparticles was easily achieved through the swelling of the microgel matrix. Furthermore, the wettability of the microgel can be adjusted between hydrophilic and hydrophobic intervals, allowing for the effective and dual-responsive phase inversion of Pickering emulsions. Moreover, it has been observed that colloidosome-like microgels can lead to unique interfacial structures during the emulsification process, thereby elucidating the fundamental mechanism governing emulsion phase inversion.

Ultrasound-Guided Capsular Thyroid Injection Therapy With Dexamethasone and Lidocaine Mixture for Subacute Thyroiditis: A Single-Center Study.

OBJECTIVES: Subacute thyroiditis (SAT) is a self-limiting, inflammatory thyroid disease possibly caused by viral infection. In recent years, the incidence of SAT is increasing, especially during the pandemic of the COVID-19. This study aimed to evaluate the efficacy, safety, and recovery time of capsular thyroid injection therapy under ultrasound guidance for SAT. METHODS: A total of 73 patients with SAT were divided into two groups. Patients in group A (n = 48) received an ultrasound-guided capsular injection consisting of dexamethasone (DEX) and lidocaine in the thyroid lesion area, while patients in group B (n = 25) received oral prednisolone (PSL). The two groups were compared for pain relief and treatment duration, the recovery time of thyroid function, recurrence rates, hypothyroidism incidence, and drug-related side effects. RESULTS: The follow-up time was 1 year. In group A, the duration of pain relief, treatment, and recovery time of thyroid function were significantly shorter than that in group B (P < .05), and no statistically significant differences in recurrence rate or incidence of hypothyroidism were observed (P > .05). Weight gain was significantly higher in group A at the end of treatment (P < .001). CONCLUSIONS: Compared with oral PSL treatment, ultrasound-guided local injection of DEX and lidocaine into the capsular thyroid is a safe and effective procedure that can significantly reduce the treatment time of SAT.

Opposing functions of Fng1 and the Rpd3 HDAC complex in H4 acetylation in Fusarium graminearum.

Histone acetylation, balanced by histone acetyltransferase (HAT) and histone deacetylase (HDAC) complexes, affects dynamic transitions of chromatin structure to regulate transcriptional accessibility. However, little is known about the interplay between HAT and HDAC complexes in Fusarium graminearum, a causal agent of Fusarium Head Blight (FHB) that uniquely contains chromosomal regions enriched for house-keeping or infection-related genes. In this study, we identified the ortholog of the human inhibitor of growth (ING1) gene in F. graminearum (FNG1) and found that it specifically interacts with the FgEsa1 HAT of the NuA4 complex. Deletion of FNG1 led to severe growth defects and blocked conidiation, sexual reproduction, DON production, and plant infection. The fng1 mutant was normal in H3 acetylation but significantly reduced in H4 acetylation. A total of 34 spontaneous suppressors of fng1 with faster growth rate were isolated. Most of them were still defective in sexual reproduction and plant infection. Thirty two of them had mutations in orthologs of yeast RPD3, SIN3, and SDS3, three key components of the yeast Rpd3L HDAC complex. Four mutations in these three genes were verified to suppress the defects of fng1 mutant in growth and H4 acetylation. The rest two suppressor strains had a frameshift or nonsense mutation in a glutamine-rich hypothetical protein that may be a novel component of the FgRpd3 HDAC complex in filamentous fungi. FgRpd3, like Fng1, localized in euchromatin. Deletion of FgRPD3 resulted in severe growth defects and elevated H4 acetylation. In contract, the Fgsds3 deletion mutant had only a minor reduction in growth rate but FgSIN3 appeared to be an essential gene. RNA-seq analysis revealed that 48.1% and 54.2% of the genes with altered expression levels in the fng1 mutant were recovered to normal expression levels in two suppressor strains with mutations in FgRPD3 and FgSDS3, respectively. Taken together, our data showed that Fng1 is important for H4 acetylation as a component of the NuA4 complex and functionally related to the FgRpd3 HDAC complex for transcriptional regulation of genes important for growth, conidiation, sexual reproduction, and plant infection in F. graminearum.

PLDP-FL: Federated Learning with Personalized Local Differential Privacy.

As a popular machine learning method, federated learning (FL) can effectively solve the issues of data silos and data privacy. However, traditional federated learning schemes cannot provide sufficient privacy protection. Furthermore, most secure federated learning schemes based on local differential privacy (LDP) ignore an important issue: they do not consider each client's differentiated privacy requirements. This paper introduces a perturbation algorithm (PDPM) that satisfies personalized local differential privacy (PLDP), resolving the issue of inadequate or excessive privacy protection for some participants due to the same privacy budget set for all clients. The algorithm enables clients to adjust the privacy parameters according to the sensitivity of their data, thus allowing the scheme to provide personalized privacy protection. To ensure the privacy of the scheme, we have conducted a strict privacy proof and simulated the scheme on both synthetic and real data sets. Experiments have demonstrated that our scheme is successful in producing high-quality models and fulfilling the demands of personalized privacy protection.

The Fng3 ING protein regulates H3 acetylation and H4 deacetylation by interacting with two distinct histone-modifying complexes.

The steady-state level of histone acetylation is maintained by histone acetyltransferase (HAT) and histone deacetylase (HDAC) complexes. INhibitor of Growth (ING) proteins are key components of the HAT or HDAC complexes but their relationship with other components and roles in phytopathogenic fungi are not well-characterized. Here, the FNG3 ING gene was functionally characterized in the wheat head blight fungus Fusarium graminearum. Deletion of FNG3 results in defects in fungal development and pathogenesis. Unlike other ING proteins that are specifically associated with distinct complexes, Fng3 was associated with both NuA3 HAT and FgRpd3 HDAC complexes to regulate H3 acetylation and H4 deacetylation. Whereas FgNto1 mediates the FgSas3-Fng3 interaction in the NuA3 complex, Fng3 interacted with the C-terminal region of FgRpd3 that is present in Rpd3 orthologs from filamentous fungi but absent in yeast Rpd3. The intrinsically disordered regions in the C-terminal tail of FgRpd3 underwent phase separation, which was important for its interaction with Fng3. Furthermore, the ING domain of Fng3 is responsible for its specificities in protein-protein interactions and functions. Taken together, Fng3 is involved in the dynamic regulation of histone acetylation by interacting with two histone modification complexes, and is important for fungal development and pathogenicity.

Multifunctional Silica-Modified Hybrid Microgels Templated from Inverse Pickering Emulsions.

Microgels are regarded as soft colloids with environmental responsiveness. However, the majority of reported microgels are inherently hydrophilic, resulting in aqueous dispersions, and only used in water-based applications. Herein, we reported an efficient method for hybridization of poly(N-isopropylacrylamide) microgel by coating hydrophobic silica nanoparticles on their surface. The resultant hybrid microgel had switchable surface wettability and could be dispersed in both aqueous and oil phases. Meanwhile, the coated hydrophobic silica nanoparticles solved the difficulty in redispersing microgels caused by particle aggregation and film formation during the drying process, providing a significant advantage in dried storage. Furthermore, the introduction of hydrophobic silica nanoparticles endowed the hybrid microgel with a variety of applications, including cargo encapsulation, active release induced by emulsion reversion, and trace water absorption.

Water-in-Oil Pickering Emulsions Stabilized by Hydrophobized Protein Microspheres.

Water-in-oil (w/o) Pickering emulsions have gained considerable attention in colloid science and daily applications. However, for the formation of w/o emulsions, especially those with high internal water content, the particulate stabilizers are required to be sufficiently hydrophobic, and synthetic or chemically modified particles have been mostly reported until now, which are not biocompatible and sustainable. We present a zein protein-based microsphere derived from the Pickering emulsion template, in which protein microspheres are feasibly in situ hydrophobized by silica nanoparticles, enabling the stabilization of w/o Pickering emulsions. The effects of microsphere concentration, water/oil volume ratio, oil types, and pH on the stabilization of prepared w/o emulsions are systematically studied, revealing prominent characteristics of the controllable size, high water fraction, universal adaptation of oils, as well as broad pH stability. As a demonstration, the Pickering emulsion effectively encapsulates vitamin C and shows high stability for long storage duration against ultraviolet radiation/heat. Therefore, this novel proteinaceous particle-stabilized w/o Pickering emulsion has great potential in the delivery and protection of water-soluble bioactive substrates.

Characterization of a novel mitovirus isolated from the phytopathogenic fungus Fusarium pseudograminearum.

Mycoviruses are widespread in all major groups of plant-pathogenic fungi. So far, only one mycovirus has been reported to be associated with Fusarium pseudograminearum, the causal agent of Fusarium crown rot of wheat. In this study, a double-stranded RNA (dsRNA) segment was isolated from F. pseudograminearum strain JW2-1, and the sequence of its full-length cDNA (3077 nucleotides) was determined. Sequence analysis using the fungal mitochondrial genetic code (UGA coding for tryptophan) indicated that a single large open reading frame (ORF) is present on the positive strand of this dsRNA segment. The ORF encodes a putative RNA-dependent RNA polymerase (RdRp) of 748 amino acids (aa) with a molecular mass of 83.46 kDa. BLASTp analysis revealed that its aa sequence was 28.49-44.03% identical to those of viruses of the family Mitoviridae, with the most similarity to the corresponding RdRp sequences of Ophiostoma mitovirus 1c (44.03% identity) and Ophiostoma mitovirus 1b (40.33% identity). Phylogenetic analysis showed that this mycovirus, designated as "Fusarium pseudograminearum mitovirus 1" (FpgMV1), should be classified as a member of a new species in the earlier proposed genus "Duamitovirus" within the family Mitoviridae. To our best of our knowledge, this is the first report of a mitovirus infecting F. pseudograminearum.

First Report of Maize Seedling Blight Caused by Fusarium pseudograminearum in China.

Maize (Zea mays L.) is one of the most important food and feed crops in China, with a cultivation area of more than 40 million hectares (http://www.fao.org/faostat/en/#data/QC). In July 2021, a serious maize seeding blight occurred in Changjia Town, Gaoqing Country, Zibo City, Shandong Province, China, and the disease incidence was up to 50% in some fields. The root system of infected plants displayed poor development. The primary roots were brown and rotted. The leaves at the base of the plants were drying up, then the whole plant withered. To determine the cause agent of the disease, symptomatic roots of diseased seedlings were collected and surface-sterilized (70% ethanol for 30 s and 3% sodium hypochlorite (NaClO) for 90 s), subsequently rinsed three times with sterile distilled water, placed on potato dextrose agar (PDA), then incubated at 25°C for 2 days. Two cultures with similar morphological characteristics were purified through single-spore isolation technique and identified by morphology and molecular methods as Fusarium pseudograminearum O'Donnell & T. Aoki 1999. Plentiful macroconidia formed in 5-day-old carboxymethyl cellulose (CMC) cultures; microconidia were absent. Macroconidia were thick-walled and curved, usually 3- to 5- septa, 31.6 ± 0.6 µm × 4.8 ± 0.1 µm (n = 50). Colony pigmentation on PDA was pink to red, with white to pink aerial mycelia on PDA cultures was abundant and filled the petri dishes. For molecular identification, the rDNA internal transcribed spacer (ITS) gene and translation elongation factor 1 alpha (TEF-1α) gene of two isolates (SAIA41B and SAIA41C) were amplified with ITS1/ITS4 (White et al., 1990) and EF-1/EF-2 (O'Donnell et al., 1998), respectively. Blastn analysis of both the ITS sequence (accession numbers OM108101 and OM108102) and TEF-1α sequence (accession numbers OM142205 and OM142206) revealed 100% (481/481 bp for ITS and 637/637 bp for TEF-1α) sequence identity with the sequences of F. pseudograminearum reported in GenBank (MW699613 for ITS and JN862232 for TEF-1α). The molecular identification was further confirmed by the F. pseudograminearum species-specific PCR primers Fp1-1/Fp1-2 (Aoki and O'Donnell 1999). The expected 523-bp fragments were obtained for isolates SAIA41B and SAIA41C. In the pathogenicity test, healthy germinating maize roots (Zhengdan958) were inoculated with PDA culture blocks of isolate SAIA41C. Plants inoculated only with PDA culture blocks served as controls. Maize plants were put in petri dishes and placed in an incubator with a 12-h photoperiod at 25 oC and 100% relative humidity. Seven days later, roots of the plants inoculated with isolate SAIA41C were poorly developed and became brown necrotic and rotted, which were identical to the symptoms observed in the fields, whereas the roots of control plants were developed normally. The pathogen was re-isolated from the necrotic tissue of the inoculated roots but not from the control plants, and its identity was confirmed by PCR with the primes Fp1-1/Fp1-2 described above, fulfilling Koch's Postulates. To our knowledge, this is the first report of maize seedling blight caused by F. pseudograminearum in China. Our finding indicates the potential spread of F. pseudograminearum on maize, and more attention should be paid to prevention and control of maize seedling blight caused by F. pseudograminearum. The author(s) declare no conflict of interest. Acknowledgements: This research was supported by National Natural Science Foundation of China (No. 32102181), Shandong Provincial Natural Science Foundation (No. ZR2021QC059), Wheat Industry Technology System of Shandong Province (No. SDAIT-01-10), and Agricultural Science and Technology Innovation Project of SAAS (No. CXGC2021A38 and CXGC2021A33).

A Direct Position Determination Method Based on Subspace Orthogonality in Cross-Spectra under Multipath Environments.

Without the estimation of the intermediate parameters, the direct position determination (DPD) method can achieve higher localization accuracy than conventional two-step methods. However, multipath environments are still a key problem, and complex high-dimensional matrix operations are required in most DPD methods. In this paper, a time-difference-of-arrival-based (TDOA-based) DPD method is proposed based on the subspace orthogonality in the cross-spectra between the different sensors. Firstly, the cross-spectrum between the segmented received signal and reference signal is calculated and eigenvalue decomposition is performed to obtain the subspaces. Then, the cost functions are constructed by using the orthogonality of subspace. Finally, the location of the radiation source is obtained by searching the superposition of these cost functions in the target area. Compared with other DPD methods, our proposed DPD method leads to better localization accuracy with less complexity. The superiority of this method is verified by both simulated and real measured data when compared to other TDOA and DPD algorithms.