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E-commerce platforms apply recommendation technology to a wide variety of commercial websites to help users quickly find the product they need from a large number of products. At present, recommendation systems have been widely used in large-scale e-commerce websites, and most e-commerce shopping websites attract customers through the image information of goods. In this paper, the research status of content-based image retrieval algorithms is analysed, and how to use image content information to recommend goods is studied. A hierarchical commodity classification and retrieval system are designed. A class decision layer is used to determine the category of commodity images and then precisely retrieve the corresponding category of commodity image features. The corresponding relationship between different commodity visual features is used to recommend commodities, and a matching recommendation algorithm for commodities is proposed. Experiments show that the proposed image content-based recommendation method can coordinate with features, and its recommendation results have high accuracy in practical applications.

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The germinal center (GC) response is essential for generating memory B and long-lived Ab-secreting plasma cells during the T cell–dependent immune response. In the GC, signals via the BCR and CD40 collaboratively promote the proliferation and positive selection of GC B cells expressing BCRs with high affinities for specific Ags. Although a complex gene transcriptional regulatory network is known to control the GC response, it remains elusive how the positive selection of GC B cells is modulated posttranscriptionally. In this study, we show that methyltransferase like 14 (Mettl14)–mediated methylation of adenosines at the position N6 of mRNA (N6-methyladenosine [m6A]) is essential for the GC B cell response in mice. Ablation of Mettl14 in B cells leads to compromised GC B cell proliferation and a defective Ab response. Interestingly, we unravel that Mettl14-mediated m6A regulates the expression of genes critical for positive selection and cell cycle regulation of GC B cells in a Ythdf2-dependent but Myc-independent manner. Furthermore, our study reveals that Mettl14-mediated m6A modification promotes mRNA decay of negative immune regulators, such as Lax1 and Tipe2, to upregulate genes requisite for GC B cell positive selection and proliferation. Thus, our findings suggest that Mettl14-mediated m6A modification plays an essential role in the GC B cell response.

Adenosine deaminase acting on RNA-1 (ADAR1) is a ubiquitously expressed RNA deaminase catalyzing adenosine-to-inosine editing to prevent hyperactivated cytosolic double-stranded RNA (dsRNA) response mediated by MDA5. Here, we demonstrate that ADAR1 is essential for early B lymphopoiesis from late pro-B and large pre-B cell stages onward. ADAR1 exerts its requisite role via both MDA5-dependent and -independent pathways. Interestingly, the MDA5-dependent mechanisms regulate early pro-B to large pre-B cell transition by promoting early B cell survival. In contrast, the MDA5-independent mechanisms control large pre-B to small pre-B cell transition by regulating pre-B cell receptor (pre-BCR) expression. Moreover, we show that protein kinase R (PKR) and oligoadenylate synthetase/ribonuclease (OAS/RNase) L pathways are dispensable for ADAR1's role in early B lymphopoiesis. Importantly, we demonstrate that p150 isoform of ADAR1 exclusively accounts for ADAR1's function in early B lymphopoiesis, and its conventional dsRNA-binding, but not the Z-DNA/RNA-binding or the RNA-editing, activity is required for ADAR1's function in B cell development. Thus, our findings suggest that ADAR1 regulates early B lymphopoiesis through various mechanisms.

Summary B lymphocytes undergo metabolic reprogramming upon activation to meet the bioenergetic demands for proliferation and differentiation. Yet, little is known if and how the fate of naive B cells is metabolically regulated. Here, we specifically delete von Hippel-Lindau protein (VHL) in B cells using CD19-Cre and demonstrate that metabolic balance is essential for naive B cell survival. Loss of VHL disturbs glycolytic and oxidative metabolic balance and causes severe reduction in mature B cells. Mechanistically, the metabolic imbalance in VHL-deficient B cells, arising from over-stabilization of hypoxia-inducible factor-1α (HIF-1α), triggers reductive glutamine metabolism leading to increased Fas palmitoylation and caspase-8-mediated apoptosis. Blockade of reductive glutamine metabolic flux by lactate supplementation and ATP citrate lyase inhibition restores the metabolic balance and rectifies the impaired survival of VHL-deficient B cells. Hence, we unravel that the VHL/HIF-1α pathway is required to maintain the metabolic balance of naive B cells and ensure their survival., Graphical Abstract, Highlights • vHL ablation in naive B cells leads to diminishment of mature B cell populations • B cells lacking vHL manifest perturbed metabolism and impaired survival • vHL deficiency in B cells triggers reductive carboxylation of α-KG • Metabolic rewiring in vHL-deficient naive B cells causes caspase-8 activation, Biological Sciences; Immunology; Cell Biology

Summary TACI (transmembrane activator and calcium modulator and cyclophilin ligand interactor) plays critical roles in B cells by promoting immunoglobulin class switching and plasma cell survival. However, its expression and function in T cells remain controversial. We show here that TACI expression can be strongly induced in murine CD4+ T cells in vitro by cytokines responsible for TH17 but not TH1 or TH2 differentiation. Frequencies and numbers of TH17 cells were elevated in TACI−/− compared with wild-type mice as well as among TACI−/− versus wild-type CD4+ T cells in mixed bone marrow chimeras, arguing for a T cell-intrinsic effect in the contribution of TACI deficiency to TH17 cell accumulation. TACI−/− mice were more susceptible to severe colitis induced by dextran sodium sulfate or adoptive T cell transfer, suggesting that TACI negatively regulates TH17 function and limits intestinal inflammation in a cell-autonomous manner. Finally, transcriptomic and biochemical analyses revealed that TACI−/− CD4+ T cells exhibited enhanced activation of TH17-promoting transcription factors NFAT, IRF4, c-MAF, and JUNB. Taken together, these findings reveal an important role of TACI in constraining TH17 pathogenicity and protecting against gut disease., Graphical Abstract, Highlights • TACI expression is induced in TH17 but not TH1 or TH2 cells differentiated in vitro • TACI−/− mice have expanded TH17 and Treg populations in various organs • TACI−/− mice have enhanced susceptibility to intestinal disease • Activation of TH17-promoting transcription factors is enhanced in TACI−/− CD4+ T cells, Immunology

MicroRNAs have been shown to play a role in B‐cell differentiation and activation. Here, we found miR‐182 to be highly induced in activated B cells. However, mice lacking miR‐182 have normal B‐cell and T‐cell development. Interestingly, mutant mice exhibited a defective antibody response at early time‐points in the immunization regimen when challenged with a T‐cell‐dependent antigen. Germinal centres were formed but the generation of extrafollicular plasma cells was defective in the spleens of immunized miR‐182‐deficient mice. Mutant mice were also not able to respond to a T‐cell‐independent type 2 antigen, which typically elicited an extrafollicular B‐cell response. Taken together, the data indicated that miR‐182 plays a critical role in driving extrafollicular B‐cell antibody responses.

Since China joint the WTO, the economy has taken off, and national capital has accumulated rapidly. It has now become the second-largest economy. In the past two or three decades, with the rapid development of China’s socialist economy and the upgrading of the industrial structure, the academic college students’ talents need a longer transition time to adapt to the current upgraded economy. Along with the integration of industry and education, colleges and enterprises pay more and more attention to the cultivation and application of application-oriented talents and compound skills talents. Compared with traditional college student talents, the employment rate of application-oriented talents is relatively high. One of the school’s goals is the employment rate of students. Therefore, the talents need to explore the integration of industry and education to cater for the social and economic development of the new era. The cultivation of application-oriented talents have been valued by colleges and universities, and gradually promoted to various majors and colleges. This article mainly discusses the research on deepening the integration of industry and education in universities in Jilin Province.

Invariant natural killer T (iNKT) cells develop from CD4(+)CD8(+) double-positive (DP) thymocytes and express an invariant V(α)14–J(α)18 T-cell receptor (TCR) α-chain. Generation of these cells requires the prolonged survival of DP thymocytes to allow for V(α)14–J(α)18 gene rearrangements and strong TCR signaling to induce the expression of the iNKT lineage-specific transcription factor PLZF. Here, we report that the transcription factor Yin Yang 1 (YY1) is essential for iNKT cell formation. Thymocytes lacking YY1 displayed a block in iNKT cell development at the earliest progenitor stage. YY1-deficient thymocytes underwent normal V(α)14–J(α)18 gene rearrangements, but exhibited impaired cell survival. Deletion of the apoptotic protein BIM failed to rescue the defect in iNKT cell generation. Chromatin immunoprecipitation and deep-sequencing experiments demonstrated that YY1 directly binds and activates the promoter of the Plzf gene. Thus, YY1 plays essential roles in iNKT cell development by coordinately regulating cell survival and PLZF expression.

Tyrosine kinase c-Abl plays an important role in early B cell development. Its deletion leads to reduced pro- and pre-B cell generation in mice. However, its function in B cell terminal differentiation remains unexplored. Here, we used c-Ablf/f Aicdacre/+ mice, in which c-Abl is ablated only in antigen-activated B cells, to study the role of c-Abl in germinal center (GC) B and antibody-secreting plasma cell formation. Upon challenge with a model antigen, we found normal GC and memory B but reduced plasma cells and antigen-specific antibody response in the mutant mice. In-vitro studies revealed that plasma cells lacking c-Abl could be generated but did not accumulate in culture, indicative of survival defect. They also exhibited impaired STAT3 phosphorylation. The plasma cell defects could be rectified by introduction of Bim-deficiency or delivery of colivelin, a STAT3 activator, into c-Ablf/f Aicdacre/+ mice. Hence, c-Abl signalling regulates the survival of plasma cells.

Bacteriophage-encoded serine recombinases have great potential in genetic engineering but their catalytic mechanisms have not been adequately studied. Integration of ϕBT1 and ϕC31 via their attachment (att) sites is catalyzed by integrases of the large serine recombinase subtype. Both ϕBT1 and ϕC31 integrases were found to cleave single-substrate att sites without synaptic complex formation, and ϕBT1 integrase relaxed supercoiled DNA containing a single integration site. Systematic mutation of the central att site dinucleotide revealed that cleavage was independent of nucleotide sequence, but rejoining was crucially dependent upon complementarity of the cleavage products. Recombination between att sites containing dinucleotides with antiparallel complementarity led to antiparallel recombination. Integrase-substrate pre-incubation experiments revealed that the enzyme can form an attP-integrase tetramer complex that then captures naked attB DNA, and suggested that two alternative assembly pathways can lead to synaptic complex formation.

The filamentous bacteria Streptomyces exhibit a complex life cycle involving morphological differentiation and secondary metabolism. A putative membrane protein gene sarA (sco4069), sporulation and antibiotic production related gene A, was partially characterized in Streptomyces coelicolor M145. The gene product had no characterized functional domains and was highly conserved in Streptomyces. Compared with the wild-type M145, the sarA mutant accelerated sporulation and dramatically decreased the production of actinorhodin and undecylprodigiosin. Reverse transcription-polymerase chain reaction analysis showed that SarA influenced antibiotic production by controlling the abundance of actII-orf4 and redZ messenger RNA.

The adaptor Downstream-of-Kinase (DOK) 3 functions as a negative regulator and attenuates B-cell receptor-mediated calcium signaling. Although DOK3 is dispensable for early B-cell development, its role in plasma cell (PC) differentiation is unknown. Here, we show that Dok3(-/-) mice have increased populations of T follicular-helper (Tfh) and germinal center (GC) B cells upon immunization with a T-cell-dependent antigen. However, interestingly, they generate significantly fewer PCs. Bone marrow reconstitution experiments show that the PC defect is B-cell intrinsic and due to the inability of Dok3(-/-) B cells to sustain programmed cell death 1 (PD-1) ligand 1 (PDL1) and up-regulate PD-1 ligand 2 (PDL2) expressions that are critical for PC differentiation. Overexpression of PDL2 rectifies the PC differentiation defect in Dok3(-/-) B cells. We further demonstrate that calcium signaling suppresses the transcription of PD-1 ligands. Abrogation of calcium signaling in B cells by deleting BTK or PLCγ2 or inhibiting calcineurin with cyclosporine A leads to increased expression of PD-1 ligands. Thus, our study reveals DOK3 as a nonredundant regulator of PC differentiation by up-regulating PD-1 ligand expression through the attenuation of calcium signaling.

The polycistronic mir-17-92 cluster, also known as oncomir-1, was previously shown to be essential for early B lymphopoiesis. However, its role in late-stage B-cell differentiation and function remains unexplored. Here we ablate mir-17-92 in mature B cells and demonstrate that mir-17-92 is dispensable for conventional B-cell development in the periphery. Interestingly, mir-17-92-deficiency in B cells leads to enhanced homing of plasma cells to the bone marrow during T-cell-dependent immune response and selectively impairs IgG2c production. Mechanistically, mir-17-92 directly represses the expression of Sphingosine 1-phosphate receptor 1 and transcription factor IKAROS, which are, respectively, important for plasma cell homing and IgG2c production. We further show that deletion of mir-17-92 could reduce IgG2c anti-DNA autoantibody production and hence mitigate immune complex glomerulonephritis in Shp1-deficient mice prone to autoimmunity. Our results identify important roles for mir-17-92 in the regulation of peripheral B-cell function.

Germline or B-cell-specific loss of Ptpn6 gene encoding the Shp1 protein tyrosine phosphatase leads to skewed B lymphopoiesis and systemic autoimmunity. Here, to study its role in B-cell terminal differentiation, we generated Ptpn6f/fAicdaCre/+ mice with Shp1 ablated only in activated B cells. We show that Ptpn6f/fAicdaCre/+ mice have normal B-cell development but exhibit defective class-switched primary and recalled antibody response to a T-cell-dependent antigen. Germinal centres are present but do not persist and memory B cells are not formed. Interestingly, Shp1-deficient plasma cells are generated in the spleen but do not contribute to the bone marrow long-lived pool. Plasma cells lacking Shp1 exhibit aberrant α4β1 integrin activation due to dysregulated Src- and PI3-kinase signalling and manifest attenuated migration in vitro and defective bone marrow homing when reconstituted in vivo. Interrupting α4β1–VCAM-1 interaction rectifies this defect. These data suggest that Shp1 signalling is required for the establishment of a life-long protective humoral immunity., SHP-1 signalling is required for the normal development of B lymphocytes but its role in the terminal differentiation of these cells has not been fully established. Here, the authors show that SHP-1 ablation impairs the establishment of long-lived bone marrow-resident plasma cells due to aberrant integrin activation.

Mutations in TNFRSF13B, better known as transmembrane activator and calcium modulator and cyclophilin ligand interactor (TACI), contribute to common variable immunodeficiency and autoimmunity in humans. How TACI regulates these two opposing conditions is unclear, however. TACI binds the cytokines BAFF and APRIL, and previous studies using gene KO mice indicated that loss of TACI affected only T-cell–independent antibody responses. Here we demonstrate that Taci −/− mice have expanded populations of T follicular helper (T fh ) and germinal center (GC) B cells in their spleens when immunized with T-cell–dependent antigen. The increased numbers of T fh and GC B cells in Taci −/− mice are largely a result of up-regulation of inducible costimulator (ICOS) ligand on TACI-deficient B cells, given that ablation of one copy of the Icosl allele restores normal levels of T fh and GC B cells in Taci −/− mice. Interestingly, despite the presence of increased T fh and antigen-specific B cells, immunized Taci −/− mice demonstrate defective antigen-specific antibody responses resulting from significantly reduced numbers of antibody-secreting cells (ASCs). This effect is attributed to the failure to down-regulate the proapoptotic molecule BIM in Taci −/− plasma cells. Ablation of BIM could rescue ASC formation in Taci −/− mice, suggesting that TACI is more important for the survival of plasma cells than for the differentiation of these cells. Thus, our data reveal dual roles for TACI in B-cell terminal differentiation. On one hand, TACI modulates ICOS ligand expression and thereby limits the size of T fh and GC B-cell compartments and prevents autoimmunity. On the other hand, it regulates the survival of ASCs and plays an important role in humoral immunity.

In order to study functional gene expression in Streptomyces coelicolor, a mini-transposon encoding the apramycin resistance gene aac(3)IV within its inverted repeat (IR) boundaries was constructed based on IS204, which was previously identified in the genome of Nocardia asteroides YP21. The mini-transposon and IS204 transposase gene were then put on a kanamycin-resistant conjugative plasmid pDZY101 that can only replicate in Escherichia coli. After mating with S. coelicolor A3(2) M145, resistant colonies arose efficiently on both apramycin and kanamycin plates. Plasmid rescue indicated that entire plasmids were inserted into the M145 genome with cleavage at an inverted repeat junction formed by the right inverted repeat (IRR) and the last 18bp of the transposase gene, while the left inverted repeat (IRL) was untouched. Southern blot analysis of the mutants using an aac(3)IV gene probe showed that transposition of plasmid pDZY101 was genetically stable, with a single-copy insertion within the S. coelicolor M145 genome. Several mutagenesis libraries of S. coelicolor M145 were constructed using plasmid pDZY101 derivatives and the transposon insertion site was determined. The correlation between novel mutant phenotypes and previously uncharacterized genes was established and these transposon locations were widely scattered around the genome.

Streptomyces not only exhibits complex morphological differentiation but also produces a plethora of secondary metabolites, particularly antibiotics. To improve our general understanding of the complex network of undecylprodigiosin (Red) biosynthesis regulation, we used an in vivo transposition system to identify novel regulators that influence Red production in Streptomyces coelicolor M145. Using this screening system, we obtained 25 Red-deficient mutants. Twenty-four of these mutants had a transposon inserted in the previously described Red biosynthetic gene cluster and produced different amounts of another secondary metabolite, actinorhodin (Act). One mutant was shown to have an insertion in a different region of the chromosome upstream of the previously uncharacterized gene rrdA ( r egulator of redD , sco1104), which encodes a putative TetR family transcription factor. Compared with wild-type strain M145, the rrdA null mutant exhibited increased Red production and decreased Act production. A high level of rrdA expression resulted in a severe reduction in Red production and Act overproduction. Reverse transcription-PCR analysis showed that RrdA negatively regulated Red production by controlling redD mRNA abundance, while no change was observed at the transcript level of the Act-specific activator gene, actII-orf4 . The effects on Act biosynthesis might arise from competition for precursors that are common to both pathways.

The filamentous bacteria Streptomyces exhibit a complex life cycle involving morphological differentiation and secondary metabolism. A putative membrane protein gene sarA (sco4069), sporulation and antibiotic production related gene A, was partially characterized in Streptomyces coelicolor M145. The gene product had no characterized functional domains and was highly conserved in Streptomyces. Compared with the wild-type M145, the sarA mutant accelerated sporulation and dramatically decreased the production of actinorhodin and undecylprodigiosin. Reverse transcription-polymerase chain reaction analysis showed that SarA influenced antibiotic production by controlling the abundance of actII-orf4 and redZ messenger RNA.

The Streptomyces phage φBT1 encodes a site-specific integrase of the large serine recombinase subfamily. In this report, the enzymatic activity of the φBT1 integrase was characterized in vitro. We showed that this integrase has efficient integration activity with substrate DNAs containing attB and attP sites, independent of DNA supercoiling or cofactors. Both intra- and intermolecular recombinations proceed with rapid kinetics. The recombination is highly specific, and no reactions are observed between pairs of sites including attB and attL , attB and attR , attP and attL , or attP and attR or between two identical att sequences; however, a low but significant frequency of excision recombination between attL and attR is observed in the presence of the φBT1 integrase alone. In addition, for efficient integration, the minimal sizes of attB and attP are 36 bp and 48 bp, respectively. This site-specific recombination system is efficient and simple to use; thus, it could have applications for the manipulation of DNA in vitro.

Stimulation of TLR7/9 by their respective ligands leads to the activation of IκB kinase α (IKKα) and Interferon Regulatory Factor 1 (IRF-1) and results in interferon (IFN)-β production in conventional dendritic cells (cDC). However, which other signaling molecules are involved in IKKα and IRF-1 activation during TLR7/9 signaling pathway are not known. We and others have shown that Bruton's Tyrosine Kinase (BTK) played a part in TLR9-mediated cytokine production in B cells and macrophages. However, it is unclear if BTK participates in TLR7/9-induced IFN-β production in cDC. In this study, we show that BTK is required for IFN-β synthesis in cDC upon TLR7/9 stimulation and that stimulated BTK-deficient cDC are defective in the induction of IKKα/β phosphorylation and IRF-1 activation. In addition, we demonstrate that Protein Kinase C µ (PKCµ) is also required for TLR7/9-induced IRF-1 activation and IFN-β upregulation in cDC and acts downstream of BTK. Taken together, we have uncovered two new molecules, BTK and PKCµ, that are involved in TLR7/9-triggered IFN-β production in cDC.