Quantitative analysis of straight-chain/branched-chain Ratio During Enzymatic Synthesis of Dextran Based on Periodate Oxidation.

The applications of dextran depend not only on the molecular weight but also on the types and number of branches. In this study, dextran generated from Leuconostoc mesenteroides (L.M.CICC-20724) was characterized by fourier-transform infrared spectrum and nuclear magnetic resonance spectroscopy. Our analyses showed that dextran was a polysaccharide composed of d-glucose units with predominantly α(1 â†’ 6) linkages in the main chain and few α(1 â†’ 3) linkages in the branch. Periodate oxidation, a classic chemical method, was usually combined with Smith degradation and gas chromatography to analyze glycosidic linkages in polysaccharide quantitatively. In this study, we calculated the exact straight-chain/branched-chain ratio in the dextran using periodate oxidation only. The ratios obtained by periodate oxidation only were compared to the ratios obtained by nuclear magnetic resonance. The results showed that the ratios of the two groups were nearly equal, and the average relative error between the two groups was 0.83%. This method was evaluated and found to be accurate and stable. This technique provided a convenient and straightforward chemical method for the quantitative analysis of the straight-chains and branched-chains in polysaccharides which had a similar structure. The ratios during the enzymatic synthesis process of dextran were analyzed by this method and were found to be stable with a high level of approximately 95% on average.

ORFeome-based identification of biomarkers for serodiagnosis of Mycobacterium tuberculosis latent infection.

BACKGROUND: The challenges posed by Mycobacterium tuberculosis infection require the gradual removal of the pool of latent tuberculosis infection (LTBI). The current cell-immune-based diagnostic tests used to identify LTBI individuals have several irreversible drawbacks. In the present study, we attempted to identify novel diagnostic antigens for LTBI. METHODS: A high-throughput glutathione S-transferase (GST)-fusion technology was used to express over 409 TB proteins and sera from LTBI and healthy individuals was used to interrogate these GST-TB fusion proteins. RESULTS: Of 409 TB proteins, sixty-three reacted seropositive and defined the immuno-ORFeome of latent M. tuberculosis. Within the immuno-ORFeome, the rare targets were predominantly latency-associated proteins and secreted proteins, while the preferentially recognized antigens tended to be transmembrane proteins. Six of novel highly-reactive antigens had the potential to distinguish LTBI from active TB and healthy individuals. A multiple-antigen combination set was selected through analysis of various combinations. A panel of 94 archived serum samples was used to validate the diagnostic performance of the multiple-antigen combination set, which had sensitivity of 66.1% (95% CI 52.9, 77.4) and specificity of 87.5% (95% CI 70.1, 95.1). CONCLUSION: These results provide experimental evidence of the immunogenicity of novel TB proteins that are suitable for the development of serodiagnostic tools for LTBI.

MAPK phosphotase 5 deficiency contributes to protection against blood-stage Plasmodium yoelii 17XL infection in mice.

Cell-mediated immunity plays a crucial role in the development of host resistance to asexual blood-stage malaria infection. However, little is known of the regulatory factors involved in this process. In this study, we investigated the impact of MAPK phosphotase 5 (MKP5) on protective immunity against a lethal Plasmodium yoelii 17XL blood-stage infection using MKP5 knockout C57BL/6 mice. Compared with wild-type control mice, MKP5 knockout mice developed significantly lower parasite burdens with prolonged survival times. We found that this phenomenon correlated with a rapid and strong IFN-γ-dependent cellular immune response during the acute phase of infection. Inactivation of IFN-γ by the administration of a neutralizing Ab significantly reduced the protective effects in MKP5 knockout mice. By analyzing IFN-γ production in innate and adaptive lymphocyte subsets, we observed that MKP5 deficiency specifically enhanced the IFN-γ response mediated by CD4+ T cells, which was attributable to the increased stimulatory capacity of splenic CD11c+ dendritic cells. Furthermore, following vaccination with whole blood-stage soluble plasmodial Ag, MKP5 knockout mice acquired strongly enhanced Ag-specific immune responses and a higher level of protection against subsequent P. yoelii 17XL challenge. Finally, we found the enhanced response mediated by MKP5 deficiency resulted in a lethal consequence in mice when infected with nonlethal P. yoelii 17XNL. Thus, our data indicate that MKP5 is a potential regulator of immune resistance against Plasmodium infection in mice, and that an understanding of the role of MKP5 in manipulating anti-malaria immunity may provide valuable information on the development of better control strategies for human malaria.

Effect of curdlan on the gel properties and interactions of whey protein isolate gels.

This study investigated the influence of curdlan on the gel properties of whey protein isolate (WPI). Results demonstrated that curdlan significantly improved the water-holding capacity, gel strength and rheological properties of the WPI gels. Moreover, it promoted the unfolding of the molecular structures of WPI, which was manifested by the transition from α-helix to ß-sheet, an increase in free sulfhydryl content and a decrease in surface hydrophobicity. Furthermore, 4 % curdlan promoted the formation of WPI with uniform and compact elastic gel network structures, primarily attributed to disulphide bonds, hydrogen bonds and hydrophobic interactions. However, when the addition of curdlan exceeds 4 %, excessive entanglement of curdlan chains and steric hindrance effects hinder the unfolding and folding of protein structures, weaken their interaction, result in a loose network structure and affect the gel properties. In conclusion, this study demonstrates that curdlan can effectively improve the gelling properties of WPI, suggesting its potential application in low-calorie gel-based dairy products.

Pulsed electric field enhances glucose glycation and emulsifying properties of bovine serum albumin: Focus on polarization and ionization effects at a high reaction temperature.

Previous studies demonstrated that the non-thermal effects of pulsed electric fields can promote protein glycation below 40 °C, but it does not always enhance the emulsifying properties of proteins, such as in the bovine serum albumin/glucose model. Therefore, the aim of this study was to investigate the impact of non-thermal effects on the glucose glycation and emulsification properties of bovine serum albumin at 90 °C. The results of circular dichroism, surface hydrophobicity, and molecular dynamics simulations showed that the polarization effect increased the degree of glycation of bovine serum albumin-glucose conjugates from 12.82 % to 21.10 % by unfolding protein molecule, while the emulsifying stability index was increased from 79.17 to 100.73 compared with the control. Furthermore, the results of principal component analysis and Pearson correlation analysis indicated that the ionization effect and the free radicals generated by pulsed electric fields significantly (p < 0.05) inhibited browning and reduced free sulfhydryl content. This study demonstrated that pulsed electric fields combined with heating can prepare glycated proteins with good emulsifying properties in a short period of time and at temperatures lower than conventional heating while reducing energy consumption. This processing strategy has potential applications in improving the emulsifying performance of highly stable proteins.

Two haplotype-resolved genome assemblies for AAB allotriploid bananas provide insights into banana subgenome asymmetric evolution and Fusarium wilt control.

Bananas (Musa spp.) are one of the world's most important fruit crops and play a vital role in food security for many developing countries. Most banana cultivars are triploids derived from inter- and intraspecific hybridizations between the wild diploid ancestor species Musa acuminate (AA) and M. balbisiana (BB). We report two haplotype-resolved genome assemblies of the representative AAB-cultivated types, Plantain and Silk, and precisely characterize ancestral contributions by examining ancestry mosaics across the genome. Widespread asymmetric evolution is observed in their subgenomes, which can be linked to frequent homologous exchange events. We reveal the genetic makeup of triploid banana cultivars and verify that subgenome B is a rich source of disease resistance genes. Only 58.5% and 59.4% of Plantain and Silk genes, respectively, are present in all three haplotypes, with >50% of genes being differentially expressed alleles in different subgenomes. We observed that the number of upregulated genes in Plantain is significantly higher than that in Silk at one-week post-inoculation with Fusarium wilt tropical race 4 (Foc TR4), which confirms that Plantain can initiate defense responses faster than Silk. Additionally, we compared genomic and transcriptomic differences among the genes related to carotenoid synthesis and starch metabolism between Plantain and Silk. Our study provides resources for better understanding the genomic architecture of cultivated bananas and has important implications for Musa genetics and breeding.

Constructing Selenium Nanoparticles with Enhanced Storage Stability and Antioxidant Activities via Conformational Transition of Curdlan.

Selenium nanoparticles (SeNPs) are among the emerging selenium supplements because of their high bioactivity and low toxicity. However, bare SeNPs are prone to activity loss caused by aggregation and sedimentation. This study aims to stabilize SeNPs with curdlan (CUR), a polysaccharide, to maintain or even enhance their biological activity. Herein, the stable SeNPs were constructed via the unique conformational transition of CUR induced by alkali-neutralization (AN) pretreatment. The physicochemical properties and structures of the prepared SeNPs were characterized by dynamic light scattering (DLS), UV-visible spectroscopy, Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), transmission electron microscopy (TEM), and free-radical-scavenging activity assays. The results show that most SeNPs are stabilized within the triple helix of CUR that has been pretreated with high-intensity AN treatment. These amorphous, small-sized (average size was 53.6 ± 17.7 nm), and stabilized SeNPs have significantly enhanced free-radical-scavenging ability compared to the control and can be well-stabilized for at least 240 days at 4 °C. This work indicates that CUR, as a food additive, can be used to well-stabilize SeNPs by AN pretreatment and provides a facile method to prepare and enhance the stability and bioactivity of SeNPs via triple-helix conformational transition.

Subcritical and Supercritical Fluids to Valorize Industrial Fruit and Vegetable Waste.

The valorization of industrial fruit and vegetable waste has gained significant attention due to the environmental concerns and economic opportunities associated with its effective utilization. This review article comprehensively discusses the application of subcritical and supercritical fluid technologies in the valorization process, highlighting the potential benefits of these advanced extraction techniques for the recovery of bioactive compounds and unconventional oils from waste materials. Novel pressurized fluid extraction techniques offer significant advantages over conventional methods, enabling effective and sustainable processes that contribute to greener production in the global manufacturing sector. Recovered bio-extract compounds can be used to uplift the nutritional profile of other food products and determine their application in the food, pharmaceutical, and nutraceutical industries. Valorization processes also play an important role in coping with the increasing demand for bioactive compounds and natural substitutes. Moreover, the integration of spent material in biorefinery and biorefining processes is also explored in terms of energy generation, such as biofuels or electricity, thus showcasing the potential for a circular economy approach in the management of waste streams. An economic evaluation is presented, detailing the cost analysis and potential barriers in the implementation of these valorization strategies. The article emphasizes the importance of fostering collaboration between academia, industry, and policymakers to enable the widespread adoption of these promising technologies. This, in turn, will contribute to a more sustainable and circular economy, maximizing the potential of fruit and vegetable waste as a source of valuable products.

Multiomics analysis reveals the genetic and metabolic characteristics associated with the low prevalence of dental caries.

Background: Despite poor oral hygiene, the Baiku Yao (BKY) ethnic group in China presents a low prevalence of dental caries, which may be related to genetic susceptibility. Due to strict intra-ethnic marriage rule, this ethnic has an advantage in studying the interaction between genetic factors and other regulatory factors related to dental caries. Methods: Peripheral blood from a caries-free adult male was used for whole genome sequencing, and the BKY assembled genome was compared to the Han Chinese genome. Oral saliva samples were collected from 51 subjects for metabolomic and metagenomic analysis. Multiomics data were integrated for combined analysis using bioinformatics approaches. Results: Comparative genomic analysis revealed the presence of structural variations in several genes associated with dental caries. Metabolomic and metagenomic sequencing demonstrated the caries-free group had significantly higher concentration of antimicrobials and higher abundance of core oral health-related microbiota. The functional analysis indicated that cationic antimicrobial peptide resistance and the lipopolysaccharide biosynthesis pathway were enriched in the caries-free group. Conclusions: Our study provided new insights into the specific regulatory mechanisms that contribute to the low prevalence of dental caries in the specific population and may provide new evidence for the genetic diagnosis and control of dental caries.

Chromosome-level genome assembly defines female-biased genes associated with sex determination and differentiation in the human blood fluke Schistosoma japonicum.

Schistosomiasis is a neglected tropical disease of humans caused by blood flukes of the genus Schistosoma, the only dioecious parasitic flatworm. Although aspects of sex determination, differentiation and reproduction have been studied in some Schistosoma species, almost nothing is known for Schistosoma japonicum, the causative agent of schistosomiasis japonica. This mainly reflects the lack of high-quality genomic and transcriptomic resources for this species. As current genomes for S. japonicum are highly fragmented, we assembled and report a chromosome-level reference genome (seven autosomes, the Z-chromosome and partial W-chromosome), achieving a substantially enhanced gene annotation. Utilizing this genome, we discovered that the sex chromosomes of S. japonicum and its congener S. mansoni independently suppressed recombination during evolution, forming five and two evolutionary strata, respectively. By exploring the W-chromosome and sex-specific transcriptomes, we identified 35 W-linked genes and 257 female-preferentially transcribed genes (FTGs) from our chromosomal assembly and uncovered a signature for sex determination and differentiation in S. japonicum. These FTGs clustering within autosomes or the Z-chromosome exhibit a highly dynamic transcription profile during the pairing of female and male schistosomula, thereby representing a critical phase for the maturation of the female worms and suggesting distinct layers of regulatory control of gene transcription at this development stage. Collectively, these data provide a valuable resource for further functional genomic characterization of S. japonicum, shed light on the evolution of sex chromosomes in this highly virulent human blood fluke, and provide a pathway to identify novel targets for development of intervention tools against schistosomiasis.

Telomere-to-telomere assembly of cassava genome reveals the evolution of cassava and divergence of allelic expression.

Cassava is a crucial crop that makes a significant contribution to ensuring human food security. However, high-quality telomere-to-telomere cassava genomes have not been available up to now, which has restricted the progress of haploid molecular breeding for cassava. In this study, we constructed two nearly complete haploid resolved genomes and an integrated, telomere-to-telomere gap-free reference genome of an excellent cassava variety, 'Xinxuan 048', thereby providing a new high-quality genomic resource. Furthermore, the evolutionary history of several species within the Euphorbiaceae family was revealed. Through comparative analysis of haploid genomes, it was found that two haploid genomes had extensive differences in linear structure, transcriptome features, and epigenetic characteristics. Genes located within the highly divergent regions and differentially expressed alleles are enriched in the functions of auxin response and the starch synthesis pathway. The high heterozygosity of cassava 'Xinxuan 048' leads to rapid trait segregation in the first selfed generation. This study provides a theoretical basis and genomic resource for molecular breeding of cassava haploids.

Purification and characterization of anti-phytopathogenic fungi angucyclinone from soil-derived Streptomyces cellulosae.

Actinomycete strain YIM PH20352, isolated from the rhizosphere soil sample of Panax notoginseng collected in WenShang, Yunnan Province, China, exhibited antifungal activity against some phytopathogenic fungi. The structures of bioactive molecules, isolated from the ethyl acetate extract of the fermentation broth of the strain, were identified as rabelomycin (1) and dehydrorabelomycin (2) based on extensive spectroscopic analyses. Compound 1 exhibited antifungal activity against four tested root-rot pathogens of the Panax notoginseng including Plectosphaerella cucumerina, Alternaria panax, Fusarium oxysporum, and Fusarium solani with the MIC values at 32, 64, 128, and 128 µg/mL, respectively. Compound 2 exhibited antifungal activity against F. oxysporum, P. cucumerina, F. solani, and A. panax with the MIC values at 64, 64, 128, and 128 µg/mL, respectively. Based on the phylogenetic analyses, the closest phylogenetic relative of strain YIM PH20352 is Streptomyces cellulosae NBRC 13027 T (AB184265) (99.88%), so strain YIM PH20352 was identified as Streptomyces cellulosae. To the best of our knowledge, this is the first report of rabelomycin and rabelomycin-type antibiotics from Streptomyces cellulosae and their antifungal activity against root-rot pathogens of the Panax notoginseng.

A Chromosome Level Genome Assembly of a Winter Turnip Rape (Brassica rapa L.) to Explore the Genetic Basis of Cold Tolerance.

Winter rapeseed (Brassica rapa L.) is an important overwintering oilseed crop that is widely planted in northwest China and suffers chronic low temperatures in winter. So the cold stress becomes one of the major constraints that limit its production. The currently existing genomes limit the understanding of the cold-tolerant genetic basis of rapeseed. Here we assembled a high-quality long-read genome of B. rapa "Longyou-7" cultivar, which has a cold-tolerant phenotype, and constructed a graph-based pan-genome to detect the structural variations within homologs of currently reported cold-tolerant related genes in the "Longyou-7" genome, which provides an additional elucidation of the cold-tolerant genetic basis of "Longyou-7" cultivar and promotes the development of cold-tolerant breeding in B. rapa.

Development and Evaluation of a Fusion Polyprotein Based on HspX and Other Antigen Sequences for the Serodiagnosis of Tuberculosis.

Background: The lack of suitable diagnostic tools contributes to the high prevalence of tuberculosis (TB) worldwide. Serological tests, based on multiple target antigens, represent an attractive option for diagnosis of this disease due to their rapidity, convenience, and low cost. Methods: Measures to reduce non-specific reactions and thereby improve the specificity of serological tests were investigated, including blocking antibodies against common bacteria in serum samples and synthesizing polypeptides covering non-conserved dominant B-cell epitopes of antigens. In addition, a fusion polyprotein containing HspX and eight other antigen sequences was constructed and expressed to increase overall sensitivity of the tests. Results: Inclusion of Escherichia coli lysate partially increased the specificity of the serological tests, while synthesis and inclusion of peptides containing non-conserved sequences of TB antigens as well as dominant B-cell epitopes reduced non-specific reactions without a decrease in sensitivity of the tests. A polyprotein fusing HspX and eight other antigen sequences was constructed and displayed 60.2% sensitivity, which was higher than that of HspX and the other individual antigen segments. Moreover, the specificity of the polyprotein was 93.8%, which was not significantly decreased when compared with HspX and the other individual antigen segments. Conclusions: The roles of the fusion polyprotein in the humoral immune response against TB infection were demonstrated and provide a potential novel approach for the development of TB diagnostics.

Effect of alkali-neutralization treatment on triple-helical aggregates and independent triple helices of curdlan.

Triple-helical aggregates (THAs) have been proven to affect the biological activities and functional properties of triple-helix polysaccharides. Thus, it's urgent to seek a method to reduce the size of THAs while preserving independent triple helices (ITHs). In this study, the effects of alkali-neutralization (AN) treatment on THAs and ITHs of curdlan were studied. The positive values of the Congo red test data (R2>0.99) fitted using a Logistic model indicated that AN treatment (CNaOH/HCl>0.28 mol/L) facilitated the disaggregation of THAs. Congo red test, sedimentation test, and turbidity test showed that AN treatment (CNaOH/HCl = 1.0 mol/L) significantly reduced the size of THAs to approximately 1 µm while effectively increasing the relative amount of ITHs to approximately 199 %. Fourier transform infrared spectroscopy and X-ray diffraction analysis showed that AN treatment basically unchanged the primary structure of curdlan chains, but affected the crystalline structure and the intermolecular and intramolecular hydrogen bonding of curdlan.

Dextran degradation by sonoenzymolysis: Degradation rate, molecular weight, mass fraction, and degradation kinetics.

To study dextran degradation by sonoenzymolysis, the degradation rate, the change of molecular weight, the mass fractions of fragments of certain molecular weight, and the degradation kinetics were analyzed and compared with the corresponding parameters under ultrasonic and enzymolysis treatments. The degradation rate improved greatly and the time required to stabilize the rate was shortened compared with ultrasonic treatment, for example, more than 120 min was needed at 4 W/mL for ultrasonic treatment before stabilization with the degradation rate of 77.41%, whereas 80 min was needed for sonoenzymolysis treatment with the degradation rate of 91.44%. A lower molecular weight limit was established (7.15 × 104 Da at 4 W/mL for sonoenzymolysis treatment compared with 19.61 × 104 Da at 4 W/mL for ultrasonic treatment), with decreased time to approach the new limiting molecular weight (80 min compared with more than 120 min). The mass fraction of 104-105 Da fragment increased (61.02% at 4 W/mL for sonoenzymolysis treatment compared with 42.98% at 4 W/mL for ultrasonic treatment) and the dextran degradation kinetics for sonoenzymolysis under lower ultrasonic intensity fitted the Malhotra model well. Sonoenzymolysis treatment at the ultrasonic intensity of 4 W/mL for 80 min resulted in more 104-105 Da fragments in a shorter time. The results indicated that sonoenzymolysis can be applied as an efficient method to obtain clinical dextran.

Influence of HLA-DRB1 alleles on antibody responses to PfCP-2.9-immunized and naturally infected individuals.

INTRODUCTION: The Plasmodium falciparum chimeric protein, PfCP-2.9, which consists of apical membrane antigen (AMA)-1(III) and merozoite surface protein (MSP)1-19, is a promising asexual-stage malaria vaccine currently being evaluated in clinical trials. This study attempts to investigate the potential association between human leukocyte antigen (HLA)-DRB1 genotype and antibody response against PfCP-2.9 in healthy population and malaria patients. MATERIALS AND METHODS: We investigated the HLA-DRB1 alleles in 40 participants from phase I trial and 86 malaria patients from southern China by polymerase chain reaction with allele sequence-specific primers. The antibody and cellular response against PfCP-2.9 or its components were measured by enzyme-linked immunosorbent assay and T lymphocyte proliferation assay. RESULTS: In clinical subjects, the anti-PfCP-2.9 antibody response was likely suppressed by HLA-DR6 alleles, which was consistent with the T lymphocyte proliferation assay. Nevertheless, HLA-DR7 positively correlated with antibody responses in naturally infected individuals while DR8 correlated with weaker antibody responses for all the three recombinant proteins. Moreover, parasitemia was significantly lower in samples with higher antibody levels against PfCP-2.9 or rMSP1-19, but not for rAMA-1(III). CONCLUSION: These data suggest that antibody responses against PfCP-2.9, AMA-1(III), or MSP1-19 elicited by vaccine formulation or natural infection are controlled by different HLA-II alleles. Moreover, the antibody response to MSP1-19 contributed more to protection immunity than AMA-1(III).

A Schistosoma japonicum chimeric protein with a novel adjuvant induced a polarized Th1 immune response and protection against liver egg burdens.

BACKGROUND: Schitosomiasis japonica is still a significant public health problem in China. A protective vaccine for human or animal use represents an important strategy for long-term control of this disease. Due to the complex life cycle of schistosomes, different vaccine design approaches may be necessary, including polyvalent subunit vaccines. In this study, we constructed four chimeric proteins (designated SjGP-1~4) via fusion of Sj26GST and four individual paramyosin fragments. We tested these four proteins as vaccine candidates, and investigated the effect of deviating immune response on protection roles in mice. METHODS: The immunogencity and protection efficacy of chimeric proteins were evaluated in mice. Next, the chimeric protein SjGP-3 was selected and formulated in various adjuvants, including CFA, ISA 206, IMS 1312 and ISA 70M. The titers of antigen-specific IgG, IgE and IgG subclass were measured. The effect of adjuvant on cytokine production and percentages of CD3+CD8-IFN-gamma+ cells and CD3+CD8-IL-4+ cells were analyzed at different time points. Worm burdens and liver egg counts in different adjuvant groups were counted to evaluate the protection efficacy against cercarial challenge. RESULTS: Immunization of mice with chimeric proteins provided various levels of protection. Among the four proteins, SjGP-3 induced the highest level of protection, and showed enhanced protective efficacy compared with its individual component Sj26GST. Because of this, SjGP-3 was further formulated in various adjuvants to investigate the effect of adjuvant on immune deviation. The results revealed that SjGP-3 formulated in veterinary adjuvant ISA 70M induced a lasting polarized Th1 immune response, whereas the other adjuvants, including CFA, ISA 206 and IMS 1312, generated a moderate mixed Th1/Th2 response after immunization but all except for IMS 1312 shifted to Th2 response after onset of eggs. More importantly, the SjGP-3/70M formulation induced a significant reduction in liver egg deposition at 47.0-50.3% and the number of liver eggs per female at 34.5-37.2% but less effect on worm burdens at only 17.3-23.1%, whereas no effect of the formulations with other adjuvants on the number of liver eggs per female was observed. CONCLUSION: Construction of polyvalent subunit vaccine was capable to enhance immunogenicity and protection efficacy against schistosomiasis. There was correlation of the polarized Th1 response with reduction of liver egg burdens, supporting the immune deviation strategy for schistosomiasis japonica vaccine development.

Identification of linear epitopes in SjSP-13 of Schistosoma japonicum using a GST-peptide fusion protein microplate array.

BACKGROUND: The identification and characterization of epitopes facilitate the discovery and development of new therapeutics, vaccines and diagnostics for infectious diseases. In this study, we developed a glutathione S-transferase (GST)-peptide fusion protein microplate array for the identification of linear B-cell epitopes and applied this novel method to the identification of linear B-cell epitopes of SjSP-13, an immunodiagnostic biomarker of schistosomiasis japonica. METHODS: SjSP-13 was divided into 17 overlapped peptides (p1-17), and the coding sequence of each peptide was obtained by annealing two complementary oligonucleotides. SjSP-13 peptides were expressed by fusion with an N-terminal GST tag and a C-terminal 6xHis tag. The GST-peptide-His fusion protein was specifically bound to the Immobilizer Glutathione MicroWell 96-well plates without purification. SjSP-13 peptides and core epitopes that could be recognized by sera from schistosomiasis patients were identified by ELISA and confirmed by Western blot analysis. The receiver operating characteristic (ROC) analysis was performed to determine the diagnostic validity of the identified peptide. RESULTS: Full-length GST-peptide-His fusion proteins were successfully expressed and specifically bound to the Immobilizer Glutathione MicroWell 96-well plates. Two adjacent peptides (p7 and p8) were found to be highly immunogenic in humans. The core epitope of p7 and p8 is an 11-aa peptide (80KCLDVTDNLPE90) and an 8-aa peptide (90EKIIQFAE97), respectively. The area under the ROC curve (AUC) value of the peptide which contains the two identified epitopes is 0.947 ± 0.019. The diagnostic sensitivity and specificity of the peptide is 76.7% (95% CI: 68.8-84.5%) and 100%, respectively. CONCLUSIONS: 90EKIIQFAE97 and 80KCLDVTDNLPE90 are the two linear epitopes of SjSP-13 recognized by patient sera, and could be potential serological markers for schistosomiasis japonica.

Echinosporin antibiotics isolated from Amycolatopsis strain and their antifungal activity against root-rot pathogens of the Panax notoginseng.

Actinomycete strain YIM PH20520, isolated from the rhizosphere soil sample of Panax notoginseng collected in Wenshang, Yunnan Province, China, exhibited antifungal activity against root-rot pathogens of the Panax notoginseng. The structures of bioactive molecules, isolated from the ethyl acetate extract of the fermentation broth of the strain, were identified as echinosporin (1) and 7-deoxyechinosporin (2) based on extensive spectroscopic analyses. 1 exhibited antifungal activity against four tested root-rot pathogens of Panax notoginseng include Fusarium oxysporum, Fusarium solani, Alternaria panax, and Phoma herbarum with the MIC value at 64, 64, 32, and 64 µg/mL, respectively. 2 exhibited antifungal activities against F. oxysporum, F. solani, A. panax, and P. herbarum with the MIC value at 128, 128, 64, and 128 µg/mL, respectively. Based on the phylogenetic analyses, the closest phylogenetic relative of strain YIM PH20520 is Amycolatopsis speibonae JS72T (97.69%), so strain YIM PH20520 was identified as Amycolatopsis strain. To the best of our knowledge, this is the first report of echinosporin antibiotics isolated from Amycolatopsis strain besides Streptomyces strain and their antifungal activity against four tested root-rot pathogens of the Panax notoginseng. The results provide a reliable evidence for the following related biosynthetic investigations on Amycolatopsis strain YIM PH20520 due to echinosporins antibiotics' unique tricyclic acetal-lactone structures.