The Juvenile-Hormone-Responsive Factor AmKr-h1 Regulates Caste Differentiation in Honey Bees.

Honey bees are typical model organisms for the study of caste differentiation, and the juvenile hormone (JH) is a crucial link in the regulatory network of caste differentiation in honey bees. To investigate the mechanism of JH-mediated caste differentiation, we analyzed the effect of the JH response gene AmKr-h1 on this process. We observed that AmKr-h1 expression levels were significantly higher in queen larvae than in worker larvae at the 48 h, 84 h, and 120 h larval stages, and were regulated by JH. Inhibiting AmKr-h1 expression in honey bee larvae using RNAi could lead to the development of larvae toward workers. We also analyzed the transcriptome changes in honey bee larvae after AmKr-h1 RNAi and identified 191 differentially expressed genes (DEGs) and 682 differentially expressed alternative splicing events (DEASEs); of these, many were related to honey bee caste differentiation. Our results indicate that AmKr-h1 regulates caste differentiation in honey bees by acting as a JH-responsive gene.

Insights into the missing apiosylation step in flavonoid apiosides biosynthesis of Leguminosae plants.

Apiose is a natural pentose containing an unusual branched-chain structure. Apiosides are bioactive natural products widely present in the plant kingdom. However, little is known on the key apiosylation reaction in the biosynthetic pathways of apiosides. In this work, we discover an apiosyltransferase GuApiGT from Glycyrrhiza uralensis. GuApiGT could efficiently catalyze 2″-O-apiosylation of flavonoid glycosides, and exhibits strict selectivity towards UDP-apiose. We further solve the crystal structure of GuApiGT, determine a key sugar-binding motif (RLGSDH) through structural analysis and theoretical calculations, and obtain mutants with altered sugar selectivity through protein engineering. Moreover, we discover 121 candidate apiosyltransferase genes from Leguminosae plants, and identify the functions of 4 enzymes. Finally, we introduce GuApiGT and its upstream genes into Nicotiana benthamiana, and complete de novo biosynthesis of a series of flavonoid apiosides. This work reports an efficient phenolic apiosyltransferase, and reveals mechanisms for its sugar donor selectivity.

A highly selective C-rhamnosyltransferase from Viola tricolor and insights into its mechanisms.

C-Glycosides are important natural products with various bioactivities. In plant biosynthetic pathways, the C-glycosylation step is usually catalyzed by C-glycosyltransferases (CGTs), and most of them prefer to accept uridine 5'-diphosphate glucose (UDP-Glc) as sugar donor. No CGTs favoring UDP-rhamnose (UDP-Rha) as sugar donor has been reported, thus far. Herein, we report the first selective C-rhamnosyltransferase VtCGTc from the medicinal plant Viola tricolor. VtCGTc could efficiently catalyze C-rhamnosylation of 2-hydroxynaringenin 3-C-glucoside, and exhibited high selectivity towards UDP-Rha. Mechanisms for the sugar donor selectivity of VtCGTc were investigated by molecular dynamics (MD) simulations and molecular mechanics with generalized Born and surface area solvation (MM/GBSA) binding free energy calculations. Val144 played a vital role in recognizing UDP-Rha, and the V144T mutant could efficiently utilize UDP-Glc. This work provides a new and efficient approach to prepare flavonoid C-rhamnosides such as violanthin and iso-violanthin.

Lower alanine aminotransferase levels are associated with increased all-cause and cardiovascular mortality in nonalcoholic fatty liver patients.

BACKGROUND: Serum alanine aminotransferase (ALT) levels are often considered a marker to evaluate liver disease and its severity. AIM: To investigate the association between ALT levels and all-cause and cause-specific mortality in patients with nonalcoholic fatty liver disease (NAFLD). METHODS: The Third National Health and Nutrition Examination Survey (NHANES-III) from 1988 to 1994 and NHANES-III-related mortality data from 2019 onward were used to obtain the necessary data for the study. NAFLD was defined as hepatic steatosis, as diagnosed by ultrasound, with no other liver diseases. ALT levels were categorized into four groups according to the different recommended upper limits of normal (ULN) in men and women: < 0.5 ULN, 0.5-1 ULN, 1-2 ULN, and ≥ 2 ULN. The hazard ratios for all-cause mortality and cause-specific mortality were analyzed using the Cox proportional hazard model. RESULTS: Multivariate logistic regression analysis demonstrated that the odds ratio of NAFLD correlated positively with increased serum ALT levels. In patients with NAFLD, all-cause mortality and cardiovascular mortality were the highest when ALT was < 0.5 ULN, yet cancer-related mortality was the highest when ALT was ≥ 2 ULN. The same results could be found in both men and women. Univariate analysis showed that severe NAFLD with normal ALT levels had the highest all-cause and cause-specific mortality, but the difference was not statistically significant after adjustment for age and multivariate factors. CONCLUSION: The risk of NAFLD was positively correlated with ALT level, but all-cause and cardiovascular mortality were the highest when ALT was < 0.5 ULN. Regardless of the severity of NAFLD, normal or lower ALT levels were associated with higher mortality than elevated ALT levels. Clinicians should be aware that high ALT levels indicate liver injury, but low ALT levels are associated with a higher risk of death.

Functional characterization, structural basis, and regio-selectivity control of a promiscuous flavonoid 7,4'-di-O-glycosyltransferase from Ziziphus jujuba var. spinosa.

A highly efficient and promiscuous 7,4'-di-O-glycosyltransferase ZjOGT3 was discovered from the medicinal plant Ziziphus jujuba var. spinosa. ZjOGT3 could sequentially catalyse 4'- and 7-O-glycosylation of flavones to produce 7,4'-di-O-glycosides with obvious regio-selectivity. For 7,4'-dihydroxyl flavanones and 3-O-glycosylated 7,4'-dihydroxyl flavones, ZjOGT3 selectively catalyses 7-O-glycosylation. The crystal structure of ZjOGT3 was solved. Structural analysis, DFT calculations, MD simulations, and site-directed mutagenesis reveal that the regio-selectivity is mainly controlled by the enzyme microenvironment for 7,4'-dihydroxyl flavones and 3-O-glycosylated 7,4'-dihydroxyl flavones. For 7,4'-dihydroxyl flavanones, the selectivity is mainly controlled by intrinsic reactivity. ZjOGT3 is the first plant flavonoid 7,4'-di-O-glycosyltransferase with a crystal structure. This work could help understand the catalytic mechanisms of multi-site glycosyltransferases and provides an efficient approach to synthesise O-glycosides with medicinal potential.

A Global Survey of the Full-Length Transcriptome of Apis mellifera by Single-Molecule Long-Read Sequencing.

As important pollinators, honey bees play a crucial role in both maintaining the ecological balance and providing products for humans. Although several versions of the western honey bee genome have already been published, its transcriptome information still needs to be refined. In this study, PacBio single-molecule sequencing technology was used to sequence the full-length transcriptome of mixed samples from many developmental time points and tissues of A. mellifera queens, workers and drones. A total of 116,535 transcripts corresponding to 30,045 genes were obtained. Of these, 92,477 transcripts were annotated. Compared to the annotated genes and transcripts on the reference genome, 18,915 gene loci and 96,176 transcripts were newly identified. From these transcripts, 136,554 alternative splicing (AS) events, 23,376 alternative polyadenylation (APA) sites and 21,813 lncRNAs were detected. In addition, based on the full-length transcripts, we identified many differentially expressed transcripts (DETs) between queen, worker and drone. Our results provide a complete set of reference transcripts for A. mellifera that dramatically expand our understanding of the complexity and diversity of the honey bee transcriptome.

[Simulation and Regulation of Sustainable Utilization of Water Resources in China Based on Improved Water Resources Ecological Footprint Model].

The original ecological footprint model of water resources was improved here to explore the rational policy of water resources development and utilization. Aiming to address the problems of high complexity, weak applicability, and insufficient systematicness and dynamics of the existing water resources ecological footprint model, the grey water footprint was introduced into the model to quantify the water for decontamination. In the calculation of the water resources ecological footprint index, the rainwater collection project, seawater desalination, and water resources regeneration, unconventional water sources were considered, and when combined with the system dynamics simulation technology, the SD model of water resources sustainable utilization in China was established. We carried out research on the regulation and control of sustainable utilization of water resources in China. The results showed that the development and utilization of water resources in China remained within the ecological carrying capacity as a whole from 2000 to 2017, and the development of water resources still had potential, but the supply and demand of water resources were unbalanced. Given this, from the perspective of throttling, open-source, and pollution control, six control schemes for sustainable utilization of water resources in China were set up, including the continuation of the current situation, green throttling, pollution control, strict planning for water source development, and comprehensive treatment. Among them, the comprehensive coordination plan for 2018-2050 could properly solve the problem of water resources supply and demand under the conditions of meeting the ecological sustainability of water resources and reasonable water resources load and was the best regulation plan to realize the sustainable utilization of water resources in China. At present, the development of water resources in China lags, which does not match the growth rate of social and economic development on water resources consumption. It is necessary to further strengthen the efforts of open-source, water-saving, and pollution control based on the original policies, so as to alleviate the ecological stress of water resources.

Phenotypic dimorphism between honeybee queen and worker is regulated by complicated epigenetic modifications.

Phenotypic dimorphism between queens and workers is an important biological characteristic of honeybees that has been the subject of intensive research. The enormous differences in morphology, lifespan, physiology, and behavior between queens and workers are caused by a complicated set of factors. Epigenetic modifications are considered to play an important role in this process. In this study, we analyzed the differences in chromosome interactions and H3K27ac and H3K4me1 modifications between the queens and workers using high-throughput chromosome conformation capture (Hi-C) and Chromatin immunoprecipitation followed by sequencing (ChIP-Seq) technologies. We found that the queens contain more chromosome interactions and more unique H3K27ac modifications than workers; in contrast, workers have more H3K4me1 modifications than queens. Moreover, we identified Map3k15 as a potential caste gene in queen-worker differentiation. Our results suggest that chromosomal conformation and H3K27ac and H3K4me1 modifications are involved in regulating queen-worker differentiation, which reveals that the queen-worker phenotypic dimorphism is regulated by multiple epigenetic modifications.

The diverging epigenomic landscapes of honeybee queens and workers revealed by multiomic sequencing.

The role of the epigenome in phenotypic plasticity is unclear presently. Here we used a multiomics approach to explore the nature of the epigenome in developing honey bee (Apis mellifera) workers and queens. Our data clearly showed distinct queen and worker epigenomic landscapes during the developmental process. Differences in gene expression between workers and queens become more extensive and more layered during the process of development. Genes known to be important for caste differentiation were more likely to be regulated by multiple epigenomic systems than other differentially expressed genes. We confirmed the importance of two candidate genes for caste differentiation by using RNAi to manipulate the expression of two genes that differed in expression between workers and queens were regulated by multiple epigenomic systems. For both genes the RNAi manipulation resulted in a decrease in weight and fewer ovarioles of newly emerged queens compared to controls. Our data show that the distinct epigenomic landscapes of worker and queen bees differentiate during the course of larval development.

Transcriptome changes of Apis mellifera female embryos with fem gene knockout by CRISPR/Cas9.

The sex of honey bees is decided by a regulatory cascade comprising of csd, fem and Amdsx. In order to further identify other genes involved in sex determination and differentiation of honey bees in the early stages of embryo development, the CRISPR/Cas9 method was used to knock out fem gene in the embryonic stage of diploid western honey bees, and RNA-seq was used to analyze gene expression changes in the embryo after fem knockout. Finally, we found that the bees had undergone gender changes due to fem knockout. A total of 155 differentially expressed genes (DEGs) were obtained, with 48 up-regulated and 107 down-regulated DEGs in the mutant group compared to the control group. Of them, many genes are related to sex development or differentiation. In addition, 1502 differentially expressed alternative splicing events (DEASEs) related to 1011 genes, including the main honey bee sex-determining genes csd, tra2, fem, and Amdsx, were identified between the mutant group and control group, indicating that fem regulates alternative splicing of a large number of downstream genes. Our results provide valuable clues for further investigating the molecular mechanism of sex determination and differentiation in honey bees.

An Ideal Hallmark Closest to Complete Cure of Chronic Hepatitis B Patients: High-sensitivity Quantitative HBsAg Loss.

In the era of antiviral therapy, the main goal of treatment has shifted from the persistent inhibition of hepatitis B virus (HBV) replication to the pursuit of serological clearance of HBs surface antigen (HBsAg). Based on the life cycle of HBV, HBsAg originates from covalently closed circular DNA (cccDNA) and integrated HBV DNA, thus reflecting their transcriptional activity. Complete HBsAg loss may mean elimination or persistent inactivity of the HBV genome including cccDNA and integrated HBV DNA. HBsAg loss improves the recovery of abnormal immune function, which in turn, may further promote the clearance of residual viruses. Combined with functional cure and the great improvement of clinical outcomes, the continuous seroclearance of high-sensitivity quantitative HBsAg may represent the complete cure of chronic hepatitis B (CHB). For many other risk factors besides HBV itself, patients with HBsAg loss still need regular monitoring. In this review, we summarized the evolution of CHB treatment, the origin of serum HBsAg, the pattern of HBsAg seroclearance, and the effect of HBsAg loss on immune function and disease outcomes. In addition, we discuss the significance of high-sensitivity HBsAg detection and its possibility as a surrogate of complete cure.

Hepatitis B functional cure and immune response.

Hepatitis B virus (HBV) is a hepatotropic virus, which damage to hepatocytes is not direct, but through the immune system. HBV specific CD4+ T cells can induce HBV specific B cells and CD8+ T cells. HBV specific B cells produce antibodies to control HBV infection, while HBV specific CD8+ T cells destroy infected hepatocytes. One of the reasons for the chronicity of HBV infection is that it cannot effectively activate adoptive immunity and the function of virus specific immune cells is exhausted. Among them, virus antigens (including HBV surface antigen, e antigen, core antigen, etc.) can inhibit the function of immune cells and induce immune tolerance. Long term nucleos(t)ide analogues (NAs) treatment and inactive HBsAg carriers with low HBsAg level may "wake up" immune cells with abnormal function due to the decrease of viral antigen level in blood and liver, and the specific immune function of HBV will recover to a certain extent, thus becoming the "dominant population" for functional cure. In turn, the functional cure will further promote the recovery of HBV specific immune function, which is also the theoretical basis for complete cure of hepatitis B. In the future, the complete cure of chronic HBV infection must be the combination of three drugs: inhibiting virus replication, reducing surface antigen levels and specific immune regulation, among which specific immunotherapy is indispensable. Here we review the relationship, mechanism and clinical significance between the cure of hepatitis B and immune system.

Incomplete response to ursodeoxycholic acid in primary biliary cholangitis: criteria, epidemiology, and possible mechanisms.

INTRODUCTION: As a common autoimmune disease with the characteristic of early complication, primary biliary cholangitis (PBC) leads to an increasing number of mortalities among people with end-stage liver disease (ESLD) waiting for liver transplantation. Ursodeoxycholic acid (UDCA) is the only approved first-line medicine for PBC, and a good response to treatment could acquire an ideal prognosis. Patients with poor UDCA response usually have more adverse outcomes and worse survival, therefore, the management of this group become a major consideration. AREAS COVERED: Due to the complexity of race and environment for PBC, different criteria for UDCA response exhibit various predictive performances. Factors affecting UDCA response conditions include gender, age, ethnicity, serum indicators, auto-antibodies, and autoimmune comorbidities, while no agreement has been reached. In this review, we mainly focus on cellular senescence, immune-mediated damage, and vitamin D deficiency as possible mechanisms for UDCA non-responders. EXPERT OPINION: The pathogenesis of PBC has yet to be clarified. Immunology-related mechanisms and therapy targets ought to be the main effort made for further study. Irrespective of the response condition, UDCA is recommended for routine administration in all PBC patients without contraindication. Ongoing clinical trials of second-line and additional therapy exhibit promising prospects.

Treatment of ursodeoxycholic acid with glucocorticoids and immunosuppressants may improve the long-term survival rate in primary biliary cholangitis patients.

Primary biliary cholangitis (PBC) is an autoimmune cholestatic liver disease. The clinical effectiveness of ursodeoxycholic acid (UDCA) plus glucocorticoids and/or immunosuppressants remains controversial in PBC patients. The study aimed to compare the efficacy of monotherapy and combination therapy in patients with PBC and to assess the factors affecting the efficacy. In this retrospective study, 266 patients diagnosed with PBC were divided into monotherapy group (UDCA), double therapy group (UDCA plus glucocorticoids or immunosuppressants), and triple therapy group (UDCA plus glucocorticoids and immunosuppressants) according to different treatments. Demographic characteristics, immune parameters, biochemistry profiles, and other indicators were evaluated at baseline, 6 months, and 1 year following treatment. The prognosis was evaluated using the Paris II standard. The liver transplant-free survival at 3, 5, 10, and 15 years was predicted by GLOBE score. All statistical analyses were conducted using SPSS (version 24) software (SPSS Inc, Chicago, IL). The long-term survival rate of the triple therapy group was significantly improved compared with the monotherapy group (P = .005). In addition, multivariate analysis showed that abnormal platelet count, alkaline phosphatase, and albumin levels were risk factors for poor response. When IgG levels were elevated but below twice the upper limit of normal, the clinical benefit was not significant compared with monotherapy (P > .05). Compared with monotherapy and double therapy, triple therapy may improve the long-term survival rate of PBC patients. Abnormal platelet count, alkaline phosphatase, and albumin levels were associated with a poor prognosis.

A Comparison of RNA Interference via Injection and Feeding in Honey Bees.

RNA interference (RNAi) has been used successfully to reduce target gene expression and induce specific phenotypes in several species. It has proved useful as a tool to investigate gene function and has the potential to manage pest populations and reduce disease pathogens. However, it is not known whether different administration methods are equally effective at interfering with genes in bees. Therefore, we compared the effects of feeding and injection of small interfering RNA (siRNA) on the messenger RNA (mRNA) levels of alpha-aminoadipic semialdehyde dehydrogenase (ALDH7A1), 4-coumarate-CoA ligase (4CL), and heat shock protein 70 (HSP70). Both feeding and injection of siRNA successfully knocked down the gene but feeding required more siRNA than the injection. Our results suggest that both feeding and injection of siRNA effectively interfere with brain genes in bees. The appropriateness of each method would depend on the situation.

Advances in plant-derived C-glycosides: Phytochemistry, bioactivities, and biotechnological production.

C-glycosides represent a large group of natural products with a C-C bond between the aglycone and the sugar moiety. They exhibit great structural diversity, wide natural distribution, and significant biological activities. By the end of 2021, at least 754 C-glycosides and their derivatives have been isolated and characterized from plants. Thus far, 66 functional C-glycosyltransferases (CGTs) have been discovered from plants, and provide green and efficient approaches to synthesize C-glycosides. Herein, advances in plant-derived C-glycosides are comprehensively summarized from aspects of structural diversity and identification, bioactivities, and biotechnological production. New strategies to discover novel C-glycosides and CGTs, as well as the applications of biotechnological methods to produce C-glycosides in the future are also discussed.

Extent and complexity of RNA processing in honey bee queen and worker caste development.

The distinct honeybee (Apis mellifera) worker and queen castes have become a model for the study of genomic mechanisms of phenotypic plasticity. Here we performed a nanopore-based direct RNA sequencing with exceptionally long reads to compare the mRNA transcripts between queen and workers at three points during their larval development. We found thousands of significantly differentially expressed transcript isoforms (DEIs) between queen and worker larvae. These DEIs were formatted by a flexible splicing system. We showed that poly(A) tails participated in this caste differentiation by negatively regulating the expression of DEIs. Hundreds of isoforms uniquely expressed in either queens or workers during their larval development, and isoforms were expressed at different points in queen and worker larval development demonstrating a dynamic relationship between isoform expression and developmental mechanisms. These findings show the full complexity of RNA processing and transcript expression in honey bee phenotypic plasticity.

GuRhaGT, a highly specific saponin 2''-O-rhamnosyltransferase from Glycyrrhiza uralensis.

A highly regio- and donor-specific 2''-O-rhamnosyltransferase GuRhaGT was characterised from the medicinal plant Glycyrrhiza uralensis. GuRhaGT could efficiently catalyse rhamnosylation at 2''-OH of the C-3 glycosyl moiety of triterpenoid saponins.

Combination therapy of ursodeoxycholic acid and glucocorticoid and (or) immunosuppressant in patients with primary biliary cholangitis: A meta-analysis.

BACKGROUND/OBJECTIVES: Primary biliary cholangitis (PBC) is a chronic inflammatory autoimmune cholestasis liver disease. There were many studies comparing a combination of glucocorticoids and/or immunosuppressants to a single UDCA therapy in PBC patients, while the literature demonstrated divergent finds. To evaluate the effectiveness of ursodeoxycholic acid (UDCA) combined with glucocorticoids and (or) immunosuppressants on biochemistry, immunology, histology, clinical symptoms, and adverse reactions of PBC from the perspective of evidence-based medicine. MATERIALS AND METHODS: PubMed, web of science, the Cochrane Library, EMBASE databases were searched to collect clinical randomized trials and self-control studies of UDCA combined with glucocorticoids and (or) immunosuppressants and UDCA monotherapy in the treatment of PBC. The retrieval time is from the establishment of the database to August 2020. Two reviewers independently screened literature, extracted data and evaluated the bias of included studies. Revman 5.3 software was used for meta-analysis. RESULTS: Six studies including 201 patients were included. The meta-analysis found that the combination therapy can improve some biochemical indexes, immunological indexes, and clinical symptoms of patients with PBC. However, combination therapy has no significant improvement in other biochemical indicators which respond to liver and bile duct damage, such as ALT, GGT, and ALB. Besides, the improvement of liver histology is limited, and the incidence of adverse events is higher. CONCLUSION: Overall, the combination therapy showed no improvement in key biochemical parameters and limited improvement in liver pathology. Besides, the side effects were more serious. Therefore, in the current treatment regimen, it is not recommended for PBC patients.

A highly selective 2''-O-glycosyltransferase from Ziziphus jujuba and De novo biosynthesis of isovitexin 2''-O-glucoside.

A novel and efficient 2''-O-glycosyltransferase ZjOGT38 was identified from Ziziphus jujuba. It could regio-selectively glycosylate 2-hydroxyflavanone C-glycosides. ZjOGT38 allowed de novo biosynthesis of isovitexin 2''-O-glucoside in E. coli.