Population genetic analysis of the Plasmodium falciparum erythrocyte binding antigen-175 (EBA-175) gene in Equatorial Guinea.

BACKGROUND: Plasmodium falciparum erythrocyte binding antigen-175 (PfEBA-175) is a candidate antigen for a blood-stage malaria vaccine, while various polymorphisms and dimorphism have prevented to development of effective vaccines based on this gene. This study aimed to investigate the dimorphism of PfEBA-175 on both the Bioko Island and continent of Equatorial Guinea, as well as the genetic polymorphism and natural selection of global PfEBA-175. METHODS: The allelic dimorphism of PfEBA-175 region II of 297 bloods samples from Equatorial Guinea in 2018 and 2019 were investigated by nested polymerase chain reaction and sequencing. Polymorphic characteristics and the effect of natural selection were analyzed using MEGA 7.0, DnaSP 6.0 and PopART programs. Protein function prediction of new amino acid mutation sites was performed using PolyPhen-2 and Foldx program. RESULTS: Both Bioko Island and Bata district populations, the frequency of the F-fragment was higher than that of the C-fragment of PfEBA-175 gene. The PfEBA-175 of Bioko Island and Bata district isolates showed a high degree of genetic variability and heterogeneity, with π values of 0.00407 & 0.00411 and Hd values of 0.958 & 0.976 for nucleotide diversity, respectively. The values of Tajima's D of PfEBA-175 on Bata district and Bioko Island were 0.56395 and - 0.27018, respectively. Globally, PfEBA-175 isolates from Asia were more diverse than those from Africa and South America, and genetic differentiation quantified by the fixation index between Asian and South American countries populations was significant (FST > 0.15, P < 0.05). A total of 310 global isolates clustered in 92 haplotypes, and only one cluster contained isolates from three continents. The mutations A34T, K109E, D278Y, K301N, L305V and D329N were predicted as probably damaging. CONCLUSIONS: This study demonstrated that the dimorphism of F-fragment PfEBA-175 was remarkably predominant in the study area. The distribution patterns and genetic diversity of PfEBA-175 in Equatorial Guinea isolates were similar another region isolates. And the levels of recombination events suggested that natural selection and intragenic recombination might be the main drivers of genetic diversity in global PfEBA-175. These results have important reference value for the development of blood-stage malaria vaccine based on this antigen.

The krüppel-like factor of Penaeus vannamei negatively regulates transcription of the small subunit hemocyanin gene as part of shrimp immune response.

Hemocyanin is a multifunctional respiratory glycoprotein, which has also been implicated in other biological functions in shrimp. Moreover, recent studies have revealed that hemocyanin is also involved in a broad range of immune-related activities in shrimp. However, in spite of the considerable interest in unraveling the reasons behind the multiple immune-related functions of hemocyanin, little is known about its transcriptional regulation. Here, DNA pull-down and Liquid Chromatography - Tandem Mass Spectrometry (LC-MS/MS) analyses were used to isolate and identify the putative transcription factor(s) that are involved in the transcriptional regulation of the small subunit hemocyanin gene of Penaeus vannamei (PvHMCs). Krüppel-like factor (designated PvKruppel), a zinc finger transcription factor homolog in P. vannamei, was identified among the putative transcription factors, while bioinformatics analysis revealed the presence of Krüppel-like factor binding site (KLF motif) on the core promoter region of PvHMCs. Mutational analysis and electrophoretic mobility shift assay (EMSA) confirmed that PvKruppel could bind to the KLF motif on the core promoter region of PvHMCs. Moreover, in response to lipopolysaccharide (LPS), Vibrio parahaemolyticus and white spot syndrome virus (WSSV) challenge, transcript levels of PvKruppel and PvHMCs were negatively correlated. Furthermore, overexpression of PvKruppel significantly reduced the promoter activity of PvHMCs, while PvKruppel knockdown by RNA interference or lipopolysaccharides (LPS) stimulation resulted in a significant increase in the transcript level of PvHMCs. Taken together, our present study provides mechanistic insights into the transcriptional regulation of PvHMCs by PvKruppel during shrimp immune response to pathogens.

c-Jun regulates the promoter of small subunit hemocyanin gene of Litopenaeus vannamei.

Hemocyanin (HMC) is a respiratory glycoprotein, which also plays multifunctional non-specific innate immune defense functions in shrimp. However, the transcriptional regulatory mechanisms of the hemocyanin gene expression have not been reported. In the present study, we cloned a 4324 bp fragment of small subunit hemocyanin (HMCs) gene of Litopenaeus vannamei including the 5'-flanking region, from upstream 2475 bp to downstream 1849 bp (exon 1-intron 1-exon 2) by genome walking method. Four deletion constructs were then generated and their promoter activity assessed using the luciferase reporter system. Interestingly, we identified an alternative promoter (+1516/+1849 bp) located in exon 2, which has stronger promoter activity than the full-length or the other constructs. Bioinformatics analyses revealed that the alternative promoter region contains two conserved binding sites of the transcription factor c-Jun. Mutational analysis and electrophoretic mobility shift assay showed that Litopenaeus vannamei c-Jun (Lvc-Jun) binds to the region +1582/+1589 bp and +1831/+1837 bp of the alternative promoter. Furthermore, overexpression of Lvc-Jun significantly increased the alternative promoter activity, while co-transfection with dsRNA-Lvc-Jun significantly reduced the alternative promoter activity of HMCs. Taken together, our present data indicate that the transcription factor Lvc-Jun is essential for the transcriptional regulation of the HMCs gene expression.

The Yin Yang 1 of Penaeus vannamei regulates transcription of the small subunit hemocyanin gene during Vibrio parahaemolyticus infection.

Hemocyanin is a respiratory protein, it is also a multifunctional immune molecule that plays a vital role against pathogen invasion in shrimp. However, the regulation of hemocyanin gene expression in shrimp hemocytes and the mechanisms involved during pathogen infection remains unclear. Here, we used DNA pull-down followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) to identify the Yin Yang 1 transcription factor homolog in Penaeus vannamei (PvYY1) as a key factor that modulates transcription of the small subunit hemocyanin gene of P. vannamei (PvHMCs) in hemocytes during Vibrio parahaemolyticus AHPND (VPAHPND) infection. Bioinformatics analysis revealed that the core promoter region of PvHMCs contains two YY1 motifs. Mutational and oligoprecipitation analyses confirmed that PvYY1 could bind to the YY1 motifs in the PvHMCs core promoter region, while truncation of PvYY1 revealed that the N-terminal domain of PvYY1 is essential for the transactivation of PvHMCs core promoter. Besides, the REPO domain of PvYY1 could repress the activity of the PvHMCs core promoter. Overexpression of PvYY1 significantly activates the promoter activity of PvHMCs core promoter, while PvYY1 knockdown significantly decreases the expression level of PvHMCs in shrimp hemocytes and survival rate of shrimp upon infection with VPAHPND. Our present study provides new insights into the transcriptional regulation of PvHMCs by PvYY1 in shrimp hemocytes during bacteria (VPAHPND) infection.

Development of an optimized RPA-PfAgo detection system for MTHFR C677T polymorphism genotyping.

This study introduces an efficient RPA-PfAgo detection system for the MTHFR C677T polymorphism, proposing a potential strategy to simplify the genotyping process. By optimizing recombinase polymerase amplification (RPA) with Pyrococcus furiosus Argonaute (PfAgo) nucleases, we achieved DNA amplification at a constant temperature. The assay was fine-tuned through meticulous primer and guide DNA selection, with optimal conditions established at 2.0 µL of MgAc, a reaction temperature of 42 °C, and a 10-minute reaction time for RPA. Further optimization of the PfAgo cleavage assay revealed the ideal concentrations of MnCl2, guide DNA, molecular beacon probes, the PfAgo enzyme, and the RPA product to maximize sensitivity and specificity. Clinical validation of 20 samples showed 100% concordance with Sanger sequencing, confirming the method's precision. The RPA-PfAgo system is a promising tool for on-site genotyping, with broad applications in personalized medicine and disease prevention.

A novel FCTF evaluation and prediction model for food efficacy based on association rule mining.

Introduction: Food-components-target-function (FCTF) is an evaluation and prediction model based on association rule mining (ARM) and network interaction analysis, which is an innovative exploration of interdisciplinary integration in the food field. Methods: Using the components as the basis, the targets and functions are comprehensively explored in various databases and platforms under the guidance of the ARM concept. The focused active components, key targets and preferred efficacy are then analyzed by different interaction calculations. The FCTF model is particularly suitable for preliminary studies of medicinal plants in remote and poor areas. Results: The FCTF model of the local medicinal food Laoxianghuang focuses on the efficacy of digestive system cancers and neurological diseases, with key targets ACE, PTGS2, CYP2C19 and corresponding active components citronellal, trans-nerolidol, linalool, geraniol, α-terpineol, cadinene and α-pinene. Discussion: Centuries of traditional experience point to the efficacy of Laoxianghuang in alleviating digestive disorders, and our established FCTF model of Laoxianghuang not only demonstrates this but also extends to its possible adjunctive efficacy in neurological diseases, which deserves later exploration. The FCTF model is based on the main line of components to target and efficacy and optimizes the research level from different dimensions and aspects of interaction analysis, hoping to make some contribution to the future development of the food discipline.

Design and development of a rapid meat detection system based on RPA-CRISPR/Cas12a-LFD.

In recent years, meat adulteration safety incidents have occurred frequently, triggering widespread attention and discussion. Although there are a variety of meat quality identification methods, conventional assays require high standards for personnel and experimental conditions and are not suitable for on-site testing. Therefore, there is an urgent need for a rapid, sensitive, high specificity and high sensitivity on-site meat detection method. This study is the first to apply RPA combined with CRISPR/Cas12a technology to the field of multiple meat identification. The system developed by parameter optimization can achieve specific detection of chicken, duck, beef, pork and lamb with a minimum target sequence copy number as low as 1 × 100 copies/µL for 60 min at a constant temperature. LFD test results can be directly observed with the naked eye, with the characteristics of fast, portable and simple operation, which is extremely in line with current needs. In conclusion, the meat identification RPA-CRISPR/Cas12a-LFD system established in this study has shown promising applications in the field of meat detection, with a profound impact on meat quality, and provides a model for other food safety control programs.

Molecular Surveillance of Artemisinin-Based Combination Therapies Resistance in Plasmodium falciparum Parasites from Bioko Island, Equatorial Guinea.

Artemisinin-based combination therapies (ACTs) resistance has emerged and could be diffusing in Africa. As an offshore island on the African continent, the island of Bioko in Equatorial Guinea is considered severely affected and resistant to drug-resistant Plasmodium falciparum malaria. However, the spatial and temporal distribution remain unclear. Molecular monitoring targeting the Pfcrt, Pfk13, Pfpm2, and Pfmdr1 genes was conducted to provide insight into the impact of current antimalarial drug resistance on the island. Furthermore, polymorphic characteristics, haplotype network, and the effect of natural selection of the Pfk13 gene were evaluated. A total of 152 Plasmodium falciparum samples (collected from 2017 to 2019) were analyzed for copy number variation of the Pfpm2 gene and Pfk13, Pfcrt, and Pfmdr1 mutations. Statistical analysis of Pfk13 sequences was performed following different evolutionary models using 96 Bioko sequences and 1322 global sequences. The results showed that the prevalence of Pfk13, Pfcrt, and Pfmdr1 mutations was 73.68%, 78.29%, and 75.66%, respectively. Large proportions of isolates with multiple copies of Pfpm2 were observed (67.86%). In Bioko parasites, the genetic diversity of Pfk13 was low, and purifying selection was suggested by Tajima's D test (-1.644, P > 0.05) and the dN/dS test (-0.0004438, P > 0.05). The extended haplotype homozygosity analysis revealed that Pfk13_K189T, although most frequent in Africa, has not yet conferred a selective advantage for parasitic survival. The results suggested that the implementation of continuous drug monitoring on Bioko Island is an essential measure. IMPORTANCE Malaria, one of the tropical parasitic diseases with a high transmission rate in Bioko Island, Equatorial Guinea, especially caused by P. falciparum is highly prevalent in this region and is commonly treated locally with ACTs. The declining antimalarial susceptibility of artemisinin-based drugs suggested that resistance to artemisinin and its derivatives is developing in P. falciparum. Copy number variants in Pfpm2 and genetic polymorphisms in Pfk13, Pfcrt, and Pfmdr1 can be used as risk assessment indicators to track the development and spread of drug resistance. This study reported for the first time the molecular surveillance of Pfpm2, Pfcrt, Pfk13, and Pfmdr1 genes in Bioko Island from 2017 to 2019 to assess the possible risk of local drug-resistant P. falciparum.

Calycosin inhibits breast cancer cell migration and invasion by suppressing EMT via BATF/TGF-ß1.

In this study, we investigated the effects of calycosin on breast cancer cell progression and their underlying mechanisms. Calycosin dose- and time-dependently inhibited proliferation, migration, and invasion by T47D and MCF-7 breast cancer cells by downregulating basic leucine zipper ATF-like transcription factor (BATF) expression. Moreover, BATF promoted breast cancer cell migration and invasiveness by increasing TGFß1 mRNA and protein levels. Bioinformatics analysis, dual luciferase reporter assays, and chromatin immunoprecipitation assays confirmed the presence of BATF-binding sites in the promoter sequence of TGFß1 gene. Calycosin treatment inhibited epithelial-mesenchymal transition (EMT) of breast cancer cells by significantly increasing E-cadherin levels and decreasing N-cadherin, Vimentin, CD147, MMP-2, and MMP-9 levels through downregulation of BATF and TGFß1. TGFß1 knockdown reduced the migration and invasiveness of BATF-overexpressing breast cancer cells, whereas incubation with TGFß1 enhanced the migration and invasiveness of calycosin-treated breast cancer cells. Our findings demonstrated that calycosin inhibited EMT and progression of breast cancer cells by suppressing BATF/TGFß1 signaling. This suggests calycosin would be a promising therapeutic option for breast cancer patients.

A visual method to detect meat adulteration by recombinase polymerase amplification combined with lateral flow dipstick.

Determining the animal source in meat and meat products is crucial to prevent meat adulteration and fraud. Conventional methods require considerable operator skills, expensive instruments and are unable to provide fast mobile on-site detection systems to detect contamination of meat products. We developed a visual method based on recombinase polymerase amplification (RPA) and a lateral flow dipstick (LFD) to identify beef (Bos taurus), sheep (Ovis aries), pork (Sus scrofa), duck (Anas platyrhynchos) and chicken (Gallus gallus). The reaction was completed within 20 min. The results were determined by the naked eye. The detection limits of the RPA-LFD assays for duck, beef, sheep, chicken and pork were 101/µL, 102/µL, 102/µL, 101/µL and 101/µL, respectively. Furthermore, the RPA-LFD assays could differentiate species in boiled, microwaved, pressure-cooked or fried samples. These RPA-LFD assays represent a rapid, mobile detection system for determining meat product contamination.

Reverse Transcription Recombinase-Aided Amplification Assay With Lateral Flow Dipstick Assay for Rapid Detection of 2019 Novel Coronavirus.

Background: The emerging Coronavirus Disease-2019 (COVID-19) has challenged the public health globally. With the increasing requirement of detection for SARS-CoV-2 outside of the laboratory setting, a rapid and precise Point of Care Test (POCT) is urgently needed. Methods: Targeting the nucleocapsid (N) gene of SARS-CoV-2, specific primers, and probes for reverse transcription recombinase-aided amplification coupled with lateral flow dipstick (RT-RAA/LFD) platform were designed. For specificity evaluation, it was tested with human coronaviruses, human influenza A virus, influenza B viruses, respiratory syncytial virus, and hepatitis B virus, respectively. For sensitivity assay, it was estimated by templates of recombinant plasmid and pseudovirus of SARS-CoV-2 RNA. For clinical assessment, 100 clinical samples (13 positive and 87 negatives for SARS-CoV-2) were tested via quantitative reverse transcription PCR (RT-qPCR) and RT-RAA/LFD, respectively. Results: The limit of detection was 1 copies/µl in RT-RAA/LFD assay, which could be conducted within 30 min at 39°C, without any cross-reaction with other human coronaviruses and clinical respiratory pathogens. Compared with RT-qPCR, the established POCT assay offered 100% specificity and 100% sensitivity in the detection of clinical samples. Conclusion: This work provides a convenient POCT tool for rapid screening, diagnosis, and monitoring of suspected patients in SARS-CoV-2 endemic areas.

Nuclear receptor E75 is a transcription suppressor of the Litopenaeus vannamei small subunit hemocyanin gene.

Hemocyanin is a respiratory protein that possesses multiple physiological and immunological functions in shrimp. However, the transcriptional regulation of the hemocyanin gene is still poorly understood. Here, the nuclear receptor E75 of Litopenaeus vannamei (LvE75) was identified as one of the transcriptional regulators that modulates the transcription of the small molecular weight hemocyanin gene of L. vannamei (LvHMCs) by inhibiting its core promoter activity in a Dual-luciferase assay. In silico analysis revealed that the core promoter (designated HsP3), which is located at +1517/+1849 bp of LvHMCs contained a putative E75 binding motif ("ACGGAAT", spanning +1812/+1818 bp). Further, LvE75 was shown to inhibit the core promoter activity by direct binding. Importantly, in vivo silencing of LvE75 resulted in a significant upregulation in the mRNA and protein expression of LvHMCs gene. Taken together, our present results provide direct evidence that LvE75 is a transcriptional suppressor of the LvHMCs gene expression.

Epidemiology, evolutionary origin, and malaria-induced positive selection effects of G6PD-deficient alleles in Chinese populations.

BACKGROUND: Although glucose-6-phosphate dehydrogenase (G6PD) deficiency is the most common inherited disorder in the Chinese population, there is scarce evidence regarding the epidemiology, evolutionary origin, and malaria-induced positive selection effects of G6PD-deficient alleles in various Chinese ethnic populations. METHODS: We performed a large population-based screening (n = 15,690) to examine the impact of selection on human nucleotide diversity and to infer the evolutionary history of the most common deficiency alleles in Chinese populations. RESULTS: The frequencies of G6PD deficiency ranged from 0% to 11.6% in 12 Chinese ethnic populations. A frequency map based on geographic information showed that G6PD deficiency was highly correlated with historical malaria prevalence in China and was affected by altitude and latitude. The five most frequently occurring G6PD gene variants were NM_001042351.3:c.1376G>T, NM_001042351.3:c.1388G>A, NM_001042351.3:c.95A>G, NM_001042351.3:c.1311T>C, and NM_001042351.3:c.1024C>T, which were distributed with ethnic features. A pathogenic but rarely reported variant site (NM_001042351.3:c.448G>A) was identified in this study. Bioinformatic analysis revealed a strong and recent positive selection targeting the NM_001042351.3:c.1376G>T allele that originated in the past 3125 to 3750 years and another selection targeting the NM_001042351.3:c.1388G>A allele that originated in the past 5000 to 6000 years. Additionally, both alleles originated from a single ancestor. CONCLUSION: These results indicate that malaria has had a major impact on the Chinese genome since the introduction of rice agriculture.