Corrigendum: Ultrasonic washing as an abiotic elicitor to induce the accumulation of phenolics of fresh-cut red cabbages: Effects on storage quality and microbial safety.

[This corrects the article DOI: 10.3389/fnut.2022.1006440.].

Ultrasonic washing as an abiotic elicitor to induce the accumulation of phenolics of fresh-cut red cabbages: Effects on storage quality and microbial safety.

Ultrasonic washing has been proved to be an abiotic elicitor to induce the accumulation of phenolics in some fruit and vegetables. However, the feasibility of ultrasonic washing on the accumulation of phenolics in fresh-cut red cabbages has not yet been reported. Therefore, the effects of ultrasonic washing on the phenolics and related phenolic metabolism enzymes of fresh-cut red cabbages, as well as quality and microbial safety during cold storage, were investigated. Firstly, the single-factor tests were used to optimize the ultrasonic processing parameters, including frequency mode, frequency amplitude, power density, frequency cycle time, and ultrasonic washing. Then the activities of the enzymes related to phenolic metabolisms after optimal ultrasound treatment were investigated, including phenylalanine ammonia-lyase (PAL), polyphenol oxidase (PPO), and peroxidase (POD). Additionally, the quality and microbial safety of fresh-cut red cabbages stored at 4°C under the optimal ultrasound treatment were evaluated. The results showed that the content of soluble phenolics (SPs) in fresh-cut red cabbages increased significantly during storage under the optimal conditions (28 ± 2 kHz, 60 W/L, 400 ms, and 20 min) compared with the control (P < 0.05). The PAL activity was activated and the PPO and POD activities were inhibited after ultrasonic washing, which contributed to the increase in the content of SPs. Meanwhile, the storage quality and microbial safety of fresh-cut red cabbages were improved. Ultrasonic washing reduced the weight loss and respiration rate and improved the color and texture characteristics. Additionally, the fresh-cut red cabbages after ultrasonic washing showed more retention of ascorbic acid (AA), total soluble proteins (TSPs), total soluble sugars (TSSs), and total soluble solids (SSs) compared with the control. Finally, ultrasonic washing effectively inhibited the growth of bacteria, molds and yeasts, which is beneficial to the extension of the shelf-life of fresh-cut red cabbages. Therefore, ultrasonic washing can be used as a tool to increase the content of SPs in fresh-cut red cabbages while retaining quality attributes and microbial safety.

Mechanism of the Passage of Angiostrongylus cantonensis across the Final Host Blood-Brain Barrier Using the Next-Generation Sequencing.

BACKGROUND: Multicellular parasites Angiostrogylus cantonensis larvae develop in the final host rat brain at the fourth stage (L4) and migrate to the lungs by the adult stage. The potential mechanism of its blood-brain barrier (BBB) passage remains unclear. METHODS: By using Illumina Hiseq/Miseq sequencing, we obtained the transcriptomes of 3 groups of adult males and 3 groups of female of A. cantonensis to generate similarly expressed genes (SEGs) between 2 genders at the adult stage. Next 2 groups of L4 expressed genes were used to compared with SEGs to create differentially expressed genes (DEGs) between 2 life stages to unlock potential mechanism of BBB passage. RESULTS: In total, we obtained 381 581 802 clean reads and 56 990 699 010 clean bases. Of these, 331 803 unigenes and 482 056 transcripts were successfully annotated. A total of 3 166 DEGs between L4 and adults SEGs were detected. Annotation of these DEGs showed 167 were down-regulated and 181 were up-regulated. Pathway analysis exhibited that calcium signaling pathway, the ECM-receptor interaction, focal adhesion, and cysteine and methionine metabolism were highly associated with DEGs. The function of these pathways might be related to BBB traversal, as well as neuro-regulation, interactions between parasite and host, environmental adaption. CONCLUSION: This study expanded the regulatory characteristics of the two important life stages of A. cantonensis. This information may provide a better appreciation of the biological features of the stages of the parasitic A. cantonensis.

The immunoenhancement effects of sea buckthorn pulp oil in cyclophosphamide-induced immunosuppressed mice.

In this study, the immunomodulatory effect of sea buckthorn (SBT) pulp oil was elucidated in immunosuppressed Balb/c mice induced by cyclophosphamide (CTX). The results showed that SBT pulp oil could reverse the decreasing trend of body weight, thymus/spleen index and hematological parameters induced by CTX. Compared with immunosuppressive mice induced by CTX, SBT pulp oil could enhance NK cytotoxicity, macrophage phagocytosis, and T lymphocyte proliferation, and regulate the proportion of T cell subsets in mesenteric lymph nodes (MLN), and promote the production of secretory immunoglobulin A (sIgA), IFN-γ, IL-2, IL-4, IL-12 and TNF-α in the intestines. In addition, SBT pulp oil can promote the production of short fatty acids (SCFAs), increase the diversity of gut microbiota, improve the composition of intestinal flora, increase the abundance of Alistipes, Bacteroides, Anaerotruncus, Lactobacillus, ASF356, and Roseburia, while decreasing the abundance of Mucispirillum, Anaeroplasma, Pelagibacterium, Brevundimonas, Ochrobactrum, Acinetobacter, Ruminiclostridium, Blautia, Ruminiclostridium, Oscillibacter, and Faecalibaculum. This study shows that SBT pulp oil can regulate the diversity and composition of intestinal microflora in CTX-induced immunosuppressive Balb/c mice, thus enhancing the intestinal mucosa and systemic immune response. The results can provide a basis for understanding the function of SBT pulp oil and its application as a new probiotic and immunomodulator.

Global survey of miRNAs and tRNA-derived small RNAs from the human parasitic protist Trichomonas vaginalis.

BACKGROUND: Small non-coding RNAs play critical regulatory roles in post-transcription. However, their characteristics in Trichomonas vaginalis, the causative agent of human sexually transmitted trichomoniasis, still remain to be determined. METHODS: Small RNA transcriptomes from Trichomonas trophozoites were deep sequenced using the Illumina NextSeq 500 system and comprehensively analyzed to identify Trichomonas microRNAs (miRNAs) and transfer RNA (tRNA)-derived small RNAs (tsRNAs). The tsRNA candidates were confirmed by stem-loop quantitative reverse transcription-PCR, and motifs to guide the cleavage of tsRNAs were predicted using the GLAM2 algorithm. RESULTS: The miRNAs were found to be present in T. vaginalis but at an extremely low abundance (0.0046%). Three categories of endogenous Trichomonas tsRNAs were identified, namely 5'tritsRNAs, mid-tritsRNAs and 3'tritsRNAs, with the 5'tritsRNAs constituting the dominant category (67.63%) of tsRNAs. Interestingly, the cleavage site analysis verified both conventional classes of tRNA-derived fragments (tRFs) and tRNA-halves in tritsRNAs, indicating the expression of tRNA-halves in the non-stress condition. A total of 25 tritsRNAs were experimentally confirmed, accounting for 78.1% of all tested candidates. Three motifs were predicted to guide the production of tritsRNAs. The results prove the expression of tRFs and tRNA-halves in the T. vaginalis transcriptome. CONCLUSIONS: This is the first report of genome-wide investigation of small RNAs, particularly tsRNAs and miRNAs, from Trichomonas parasites. Our findings demonstrate the expression profile of tsRNAs in T. vaginalis, while miRNA was barely detected. These results may promote further research aimed at gaining a better understanding of the evolution of small non-coding RNA in T. vaginalis and their functions in the pathogenesis of trichomoniasis.

Main Pathways and Ion Channels Differentially Expressed in the Transcriptome of Male and Female Adult Angiostrongylus cantonensis Using a Deep Sequencing Approach.

BACKGROUND: The adult stage is an important period in the life cycle of Angiostrongylus cantonensis, as it is at this stage that male and female worms produce thousands of fertilized eggs daily. METHODS: To explore the transcriptional details of adult male and female A. cantonensis, three groups of male and female adult worms were collected, and their transcriptome profiles were analyzed using an Illumina next-generation sequencing platform. A total of 283,910,174 clean reads were obtained, and 137,626 unigenes and 237,059 transcripts were then generated. Unigenes were successfully annotated by querying the Gene Ontology (GO), the Kyoto Encyclopedia of Genes and Genomes (KEGG), NCBI non-redundant protein sequences (NR), PFAM, STRING, and SWISS-PROT databases. Then, differentially expressed genes (DEGs) between the 2 genders were identified. The GO and KEGG databases were used for DEG annotation, and a number of DEG annotations were enriched. RESULTS: The results obtained from querying DEGs using the GO and KEGG databases revealed that male and female adult worms exhibited differences in metabolism and production. Protein phosphorylation, ion transport, and calcium transport were all significantly enriched according to GO annotation. A number of other pathways were also enriched according to KEGG enrichment annotation, including the pentose phosphate pathway, nitrogen metabolism, oocyte meiosis pathway, neuroactive ligand-receptor interaction, calcium signaling pathway, transforming growth factor ß (TGF-ß) signaling pathway etc. CONCLUSION: We hypothesized that the nervous system of the worm plays a key role in the physiological regulation of adult A. cantonensis, and based on this, the function of the calcium-signaling pathway should be investigated.

Next-Generation Sequencing Reveals That Oxidative Phosphorylation Might Be a Key Pathway Differently Expressed in the Third and Fourth Stages Larvae of Angiostrongylus cantonensis.

BACKGROUND: When Angiostrongylus cantonensis develops from the third and fourth stage, it needs to change its host from the middle host, snail to the final host, rat. However, the mechanism involved in this change remains unclear. METHODS: The transcriptome differences of the third and fourth stages of A. cantonensis were explored by next-generation Illumina Hiseq/Miseq sequencing in China, in 2018. RESULTS: Overall, 137 956 488 clean reads and 20 406 213 373 clean bases of the two stages larvae were produced. Based on the queries against the Gene Ontology (GO), NCBI non-redundant protein sequences (Nr), Swissprot, and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases, 14 204 differentially expressed genes (DEGs) were predicted. GO enrichment analysis revealed 5660 DEGs with the top s categories as followings: biological process (GO:0008150, related to 5345 DEGs), cellular component (GO:0005575, related to 5297 DEGs), molecular function (GO:0003674, related to 5290 DEGs). In KEGG enrichment analysis, 116 genes were related to oxidative phosphorylation and 49 genes involved in the glycolytic process. CONCLUSION: Metabolism changes, especially oxidative phosphorylation and glycolysis, might play a key role in A. cantonensis infection of its final rat host. Many other pathways might also contribute to the transcriptome changes between these two life stages. Overall, additional studies are needed for further details.

New Nodule Type Found in the Lungs of Pomacea canaliculata, an Intermediate Host of Angiostrongylus cantonensis.

BACKGROUND: Pomacea canaliculata (P.canaliculata) lung nodules, were commonly caused by Angiostrongylus cantonensis infection. Here, we found a new nodule type without any parasites. METHODS: Overall, 447 P. canaliculata snails were collected in Ning Bo, Zhe Jiang, China in 2018. In order to exhibit the similarities and differences between two nodules types (2018, Huzhou Zhejiang, China), both types were collected in formalin for tissue pathological sectioning. Besides, to obtain the microbial community of the new nodule, the 18S ribosomal RNA (rRNA) gene of it was amplified and analyzed using the Illumina second-generation sequencing platform. RESULTS: Although two nodules were found in the lungs of P. canaliculata, they were different in shape and pathology. Illumina sequencing indicated Poterioochromonas sp., a species of golden algae, might be the causing agent of the new nodule. CONCLUSION: We firstly found a new pathological nodule type in the lungs of P. canaliculata, and this nodule might be induced by golden algae infection, however, the direct link between the golden algae and the new nodules, as well as the nodules' impact on the snails' physiology and A. cantonensis infection require further study.

[A bite of parasite, experiences of application of documentaries into parasitology class teaching].

Medical parasitology education has been facing some difficulties, because it is a course of wide range, lacking clinical cases and concerned specimens of parasites currently. In addition, its relationship with life is not closely enough. All these reasons may impact the effect of class education negatively. Therefore, it is important to increase the vitality of parasitology education and diversify the instructional mode by using the resources from Internet. In recent years, the Discovery Channel has uploaded a documentary Monsters Inside Me online. This documentary is high professional and closely linked with parasitology. It maintains numbers of clinical cases about parasitic diseases. Each episode is about 3 minutes and shortly enough to be introduced into class teaching. However, this resource has not been fully used in domestic temporally. We found that direct introduction of the documentary into class teaching can enrich teaching forms to attract learning interest of students, and finally improve the teaching effect of class. Above that, another popular documentary A Bite of China involves many related knowledge points of parasitology. The appropriate usage of the knowledge can build up close linkage between book and life, which is extremely helpful to give students a deep impression of parasitology. In brief, it is our strong recommendation to introduce the documentary Monsters Inside Me into class.

[Preparation and characterization the polyclonal antibody of the nonstructural protein of human highly pathogenic H5N1 avian influenza viruses].

OBJECTIVE: Of this study was to prepare high sensitivity and high specificity of highly pathogenic H5N1 subtype avian influenza virus NS1 protein antibody and a preliminary assessment of its potency. METHODS: Construct pET-28a (+) recombinant vector containing the H5N1 subtype of avian influenza virus NS1 sequences of E. coli BL21 (DE3), induced expression of NS1 protein, NS1 recombinant protein was obtained by Ni-NTA column purified by affinity chromatography, and SDS-PAGE and Western Blot analysis. Purified protein antigen to immunize New Zealand white rabbits, obtained rabbit anti-NS1 serum, affinity-purified polyclonal antibodies. Using ELISA and Western Blot analysis of purified antibody titer and specificity. RESULTS: NS1 fusion protein was highly expressed in a purity of greater than 90%, with the fusion protein was used to immunize New Zealand white rabbits anti-NS1 polyclonal antibody titer of 1:80 000, and specific recognition of the H5N1 subtype of avian influenza virus NS1 protein. CONCLUSIONS: NS1 polyclonal antibodies to NS1 recombinant protein purified antigen, with better potency and specificity, and to prepare the conditions for the development of the H5N1 subtype of avian influenza virus detection kit.

[Evaluation of transfection effectiveness using fluorescein-labelled oligonucleotides and entraster-R siRNA transfection into Plasmodium falciparum].

The cultured Plasmodium falciparum parasites were synchronized twice by 5% sorbitol treatment twice (8-hour window), and then incubated at 37 degrees C for 16 h. Parasites were transfected with fluorescein-labelled oligonucleotides (group A) or fluorescein-labelled oligonucleotides+Entranster-R siRNA transfection reagent (group B). After 5 h a part of parasites was evaluated by fluorescence microscopy and flow cytometry. The rest of parasites were washed with RPMI 1640 medium, and then incubated with 500 microl new medium containing 2% fresh erythrocytes for another 12 h, and detected by flow cytometry. The fluorescein-labelled oligonucleotides were localized in erythrocytes in group B, but nearly no fluorescence was observed for group A. Flow cytometry analysis indicated that the transfection efficiency of group B [(47.40 +/- 3.39)%] was higher than that of group A [(0.60 +/- 0.27)%]. In the second cell cycle, the transfection efficiency in group B was (26.85 +/- 2.90)%, while that of group A was nearly zero. The results indicated that Entranster-R siRNA transfection reagent may increase the oligonucleotides transfection efficiency.

[Cloning and bioinformatics analysis of PFC0460w in Plasmodium falciparum].

The gene fragment of PFC0460w was amplified from RNA of Plasmodium falciparum 3D7 strain with RT-PCR, and cloned into pGEM-T easy vector. The recombinant plasmid was transformed into E. coli DH5alpha and the positive clones were selected, which were identified by PCR and sequencing. The results showed that there were three sequences of PFC0460w fragment, respectively with length of 618, 597 and 543 bp. The 618 bp fragment was completely consistent with the sequence published in PlasmoDB (GenBank No. XM_001351147), and the 597 bp and 543 bp fragments were submitted to GenBank with Accession No. of JF799872 and JF799873, respectively. 205 amino acids were encoded by the 618 bp fragment, and five kinds of protein structure were predicted by Robetta.

[Application of mind map in teaching of medical parasitology].

To improve the teaching quality of medical parasitology, mind map, a simple and effective learning method, was introduced. The mind map of each chapter was drawn by teacher and distributed to students before the class. It was helpful for teacher to straighten out the teaching idea, and for students to grasp the important learning points, perfect the class notes and improve learning efficiency. The divergent characteristics of mind map can also help to develop the students' innovation ability.

Dynamin like protein 1 participated in the hemoglobin uptake pathway of Plasmodium falciparum.

BACKGROUND: During the blood stage of malaria infection, parasites internalize in the host red blood cells and degrade massive amounts of hemoglobin for their development. Although the morphology of the parasite's hemoglobin uptake pathway has been clearly observed, little has been known about its molecular mechanisms. METHODS: The recombinant proteins from Plasmodium falciparum, dynamin like protein 1 (PfDYN1) and 2 (PfDYN2) GTPase domain, were expressed in E.coli and showed GTPase activity. By using a dynamin inhibitor, dynasore, we demonstrated the involvement of PfDYN1 in the hemoglobin uptake pathway. RESULTS: The GTPase activity of the two recombinant proteins was inhibited by dynasore in vitro. Treatment of parasite cultures with 80 micromol/L dynasore at the ring and early trophozoite stage resulted in substantial inhibition of parasite growth and in an obvious decline of hemoglobin quantum. Furthermore, reduced intracellular hemozoin accumulation and decreased uptake of the FITC-dextran were also observed, together with distinctive changes in the ultrastructure of parasites after the dynasore treatment. CONCLUSIONS: Our results show that PfDYN1 plays an important role in the hemoglobin uptake pathway of P. falciparum and suggest its possibility of being a novel target for malaria chemotherapy.

Identification of a vaccine candidate antigen, PfMAg-1, from Plasmodium falciparum with monoclonal antibody M26-32.

Monoclonal antibody M26-32 has been shown to strongly inhibit the growth of Plasmodium falciparum in vitro. To identify the target antigen of M26-32, a P. falciparum Dd2 asexual stage cDNA expression library was screened with this antibody, and a full open reading frame cDNA was obtained. This gene, named pfmag-1, encodes a polypeptide of 589 amino acids. The protein PfMAg-1 was characterized as a membrane-associated protein that expressed on the surface of merozoite during erythrocytic stage. Remarkably, at the C terminus of PfMAg-1, there are 14 copies of a deca-peptide sequence of QTDEIKND (H/N) I. This tandem repeat domain was identified to harbor the epitope of the protective M26-32 monoclonal antibody, and was also recognized by sera of patients infected with P. falciparum. Rabbit antibody elicited against this deca-peptide repeat domain effectively inhibited P. falciparum invasion in vitro. Our work suggests that PfMAg-1 is a promising malaria vaccine candidate.