Search

BackgroundBabesiosis, an infectious zoonotic parasitic disease that occurs globally, is most commonly caused by Babesia microti. For a severe infection, a combination of exchange transfusion and support-therapy is used and, for a mild infection, single antibiotics, or a combination of antibiotics and antiprotozoal drugs, are used for 7–10 days for the treatment of babesiosis; however, as these treatments have problems, a new therapy is needed. Although aetiological and molecular biology methods are often used in drug screening, these methods have disadvantages and there is no standard anti-B. microti drug screening method.MethodThis study was consisted of basal test, drug-suppressive test and drug-therapeutic test. BALB/c mice were used as the animal model and robenidine hydrochloride (ROBH) was used as a positive drug. By modifying Peter’s 4-day suppression method, immunosuppressive and subpassage tests were conducted, in combination with microscopy and real-time fluorescent quantitative PCR (qPCR), the current anti-B. microti drug screening method was optimised. SPSS was used for data analysis.Result1) In the basal test, there were significant differences in the erythrocyte infection rate (EIR) and relative value of the target gene (P = 0.011 and 0.012, respectively) among days. The blood of infected mice 28, 35, and 37 days post-infection (dpi) could infect healthy second-generation mice, even if no parasites could be observed under a light microscope. Resurgence occurred when the immunity of an infected mouse decreased to a certain extent after using an immunosuppressant.2) In the drug-suppressive test, no B. microti was observed under the light microscope in any ROBH group after drug administration. Significant differences were observed in the EIR and relative value of the target gene (both P < 0.001) between the control group and ROBH groups. No B. microti was observed after the administration of an immunosuppressant or in second-generation mice in ROBH-treated groups; however, B. microti was observed in control and proguanil hydrochloride-treated groups.3) In the drug-therapeutic test, there were significant differences in the EIR and relative value of the target gene between the 100 mg/kg ROBH groups and the control group (P = 0.049 and < 0.001, respectively) but not between ROBH groups and atovaquone-azithromycin group (P = 0.587 and 0.418, respectively). None of the second-generation mice in any drug-treated group were infected, whereas all the second-generation mice in the control group were infected; parasites could be observed in the control group from the 2nd day after the administration of an immunosuppressant, several parasites were observed in the atovaquone-azithromycin group from the 10th day after the administration of an immunosuppressant, and no parasites were observed in ROBH groups. ConclusionROBH can be used as a positive drug in anti-B. microti drug screening trials. qPCR results can be used as a judgment standard in preliminary screening tests and the combination of immunosuppressive and subpassage experiments can be used to validate drug efficacy.

Alveolar echinococcosis, caused by the larval (metacestode) stage of the tapeworm Echinococcus multilocularis, is a lethal parasitosis of the liver prevalent in the Northern Hemisphere. For chemotherapy the benzimidazole derivatives mebendazole and albendazole were introduced, which were found to disrupt the microtubules by inhibition of the polymerization of tubulin into microtubules, and β-tubulin was determined to be the drug target molecule. In the present study, we evaluated the chemosensitivity of E. multilocularis protoscoleces tubulin to mebendazole and RNA interference in vitro, and to explore whether the molecular level and ultrastructure of E. multilocularis protoscoleces microtubules change post-mebendazole and RNA interference. We identified that mebendazole is parasitostatic to E. multilocularis protoscoleces through suppression the tubulin expression and change the flame cell morphology in molecular level, besides RNA interference indicated that β 2 tubulin is probably one of the vital tubulin gene to form the flame cell and the protonephridial system tubules (collective tubes) of E. multilocularis protoscoleces. Molecular level and ultrastructure detection were performed by reverse transcription-PCR, western blotting and transmission electron microscope. The RNA interference would be probably as a parasitocidal method to disrupt the survival of PSCs, extend that the relevant tubulin maybe as potential target for drug development against AE.

High quality genome is of great significance for the mining of biological information resources of species. Up to now, the genomic information of several important economic flatfishes has been well explained. All these fishes are eyes on left side-type, and no high-quality genome of eyes on right side-type species has been reported. In this study, we applied a combined strategy involving stLFR and Hi-C technologies to generate sequencing data for constructing the chromosomal genome of Verasper variegates, which belongs to Pleuronectidae with characteristic of eyes on right side. The size of genome of V. variegatus is 556 Mb. More than 97.2% of BUSCO genes were detected, and N50 lengths of the contigs and scaffolds reached 79.8 Kb and 23.8 Mb, respectively, demonstrating the outstanding completeness and sequence continuity of the genome. A total of 22,199 protein-coding genes were predicted in the assembled genome, and more than 95% of those genes could be functionally annotated. Meanwhile, the genomic collinearity, gene family and phylogenetic analyses of similar species in Pleuronectiformes were also investigated and portrayed for metamorphosis and benthic adaptation. Sex related genes mapping has also been achieved at the chromosome level. This study is the first chromosomal level genome of a Pleuronectidae fish (V. variegatus). The chromosomal genome assembly constructed in this work will not only be valuable for conservation and aquaculture studies of the V. variegatus but will also be of general interest in the phylogenetic and taxonomic studies of Pleuronectiformes.

As a zoonotic parasitosis caused by the parasitism of Echinococcus larvae, echinococcosis imposes serious disease and economic burdens on human beings and society, and is thus a global public health issue. Its complex life history, wide distribution, the combined influence of various epidemic factors, coupled with the unique natural environment, customs, and religious beliefs in endemic areas, pose a huge challenge to the national echinococcosis control programme in China. Accurate early detection and confirmation of diagnosis of echinococcosis, the use of effective drugs, real-time surveillance of the infection status of populations and various hosts, controlling the source of infection, and blocking the route of transmission are of enormous significance for control. In this paper, the work by NIPD-CTDR on the prevention and control of echinococcosis in China is reviewed, with a view to providing reference for the further promotion of the national echinococcosis control programme.

Being a zoonotic parasitic disease, schistosomiasis was widely spread in 12 provinces of Southern China in the 1950s, severly harming human health and hindering economic development. The National Institute of Parasitic Diseases at the Chinese Center for Diseases Control and Prevention, and Chinese Center for Tropical Diseases Research (NIPD-CTDR), as the only professional institution focussing on parasitic diseases at the national level, has played an important role in schistosomiasis control in the country. In this article, we look back at the changes of schistosomiasis endemicity and the contribution of NIPD-CTDR to the national schistosomiasis control programme. We review NIPD-CTDR's activities, including field investigations, design of control strategies and measures, development of diagnostics and drugs, surveillance-response of endemic situation, and monitoringevaluation of the programme. The NIPD-CTDR has mastered the transmission status of schistosomiasis, mapped the snail distribution, and explored strategies and measures suitable for different types of endemic areas in China. With a good understanding of the life cycle of Schistosoma japonicum and transmission patterns of the disease, advanced research carried out in the NIPD-CTDR based on genomics and modern technology has made it possible to explore highly efficient and soft therapeutic drugs and molluscicides, making it possible to develop new diagnostic tools and produce vaccine candidates. In the field, epidemiological studies, updated strategies and targeted intervention measures developed by scientists from the NIPD-CTDR have contributed significantly to the national schistosomiasis control programme. This all adds up to a strong foundation for eliminating schistosomiasis in China in the near future, and recommendations have been put forward how to reach this goal.

Two new quinoline alkaloids, aaptolines A and B, were isolated from the marine sponge Aaptos aaptos. Their structures were determined by HR-ESI-MS data, NMR analysis, and X-ray crystallography. Structurally, aaptoline A is characterized as having a quinoline skeleton fused with a 1,4-dioxane motif at the C(7)-C(8) position, whereas aaptoline B possessed an intriguing 1H-pyrrolo[2,3-g]quinoline moiety. The cytotoxic assay of these compounds showed no cytotoxicity towards HepG2, A549, and PC9 cancer cell lines and had IC50 values greater than 20 μm.

Echinococcosis is a serious helminthic zoonosis with a great impact on human health and livestock husbandry. However, the clinically used drugs (benzimidazoles) have a low cure rate, so alternative drugs are urgently needed. Currently, drug screenings for echinococcosis are mainly phenotype-based, and the efficiency of identifying active compounds is very low. With a pharmacophore model generated from the structures of active amino alcohols, we performed a virtual screening to discover novel compounds with anti-echinococcal activity. Sixty-two compounds from the virtual screening were tested on Echinococcus multilocularis protoscoleces, and 10 of these compounds were found to be active. After further evaluation of their cytotoxicity, S6 was selected along with two active amino alcohols for in vivo pharmacodynamic and pharmacokinetic studies. At the two tested doses (50 and 25 mg/kg), S6 inhibited the growth of E. multilocularis in mice (14.43 and 9.53%), but no significant difference between the treatment groups and control group was observed. Treatment with BTB4 and HT3 was shown to be ineffective. During the 28 days of treatment, the death of mice in the mebendazole, HT3, and BTB4 groups indicated their toxicity. The plasma concentration of S6 administered by both methods was very low, with the Cmax being only 1 ng/ml after oral administration and below the detection limit after intramuscular administration. In addition, the plasma concentrations of BTB4 and HT3 in vitro did not reach high enough levels to kill the parasites. The toxicities of these two amino alcohols indicated that they are not suitable for further development as anti-echinococcal drugs. However, further attempts should be made to increase the bioavailability of S6 and modify its structure. In this study, we demonstrate that pharmacophore-based virtual screenings with high drug identification efficiency could be used to find novel drugs for treating echinococcosis.

A thiazole-containing cyclic depsipeptide with 11 amino acid residues, named pagoamide A (1), was isolated from laboratory cultures of a marine Chlorophyte, Derbesia sp. This green algal sample was collected from America Samoa and pagoamide A was isolated using guidance by MS/MS based molecular networking. Cultures were grown in a light and temperature-controlled environment, and harvested after several months of growth. The planar structure of pagoamide A (1) was characterized by detailed 1D- and 2D-NMR experiments along with MS and UV analysis. The absolute configurations of its amino acid residues were determined by advanced Marfey’s analysis following chemical hydrolysis and hydrazinolysis reactions. Two of the residues in pagoamide A (1), phenylalanine and serine, each occurred twice in the molecule, once in the d- and once in the l-configuration. The biosynthetic origin of pagoamide A (1) was considered in light of other natural products investigations with coenocytic green algae.

As a zoonotic parasitosis caused by the parasitism of Echinococcus larvae, echinococcosis imposes serious disease and economic burdens on human beings and society, and is thus a global public health issue. Its complex life history, wide distribution, the combined influence of various epidemic factors, coupled with the unique natural environment, customs, and religious beliefs in endemic areas, pose a huge challenge to the national echinococcosis control programme in China. Accurate early detection and confirmation of diagnosis of echinococcosis, the use of effective drugs, real-time surveillance of the infection status of populations and various hosts, controlling the source of infection, and blocking the route of transmission are of enormous significance for control. In this paper, the work by NIPD-CTDR on the prevention and control of echinococcosis in China is reviewed, with a view to providing reference for the further promotion of the national echinococcosis control programme.

Being a zoonotic parasitic disease, schistosomiasis was widely spread in 12 provinces of Southern China in the 1950s, severly harming human health and hindering economic development. The National Institute of Parasitic Diseases at the Chinese Center for Diseases Control and Prevention, and Chinese Center for Tropical Diseases Research (NIPD-CTDR), as the only professional institution focussing on parasitic diseases at the national level, has played an important role in schistosomiasis control in the country. In this article, we look back at the changes of schistosomiasis endemicity and the contribution of NIPD-CTDR to the national schistosomiasis control programme. We review NIPD-CTDR's activities, including field investigations, design of control strategies and measures, development of diagnostics and drugs, surveillance-response of endemic situation, and monitoring & evaluation of the programme. The NIPD-CTDR has mastered the transmission status of schistosomiasis, mapped the snail distribution, and explored strategies and measures suitable for different types of endemic areas in China. With a good understanding of the life cycle of Schistosoma japonicum and transmission patterns of the disease, advanced research carried out in the NIPD-CTDR based on genomics and modern technology has made it possible to explore highly efficient and soft therapeutic drugs and molluscicides, making it possible to develop new diagnostic tools and produce vaccine candidates. In the field, epidemiological studies, updated strategies and targeted intervention measures developed by scientists from the NIPD-CTDR have contributed significantly to the national schistosomiasis control programme. This all adds up to a strong foundation for eliminating schistosomiasis in China in the near future, and recommendations have been put forward how to reach this goal.

Babesiosis is an emerging zoonotic disease that is typically caused by Babesia microti infection. Clinical treatment of B. microti infection is challenging; hence, it is crucial to find new effective drugs. The current laboratory screening methods for anti-B. microti drugs are not optimized. We conducted drug-suppressive and drug-therapeutic tests to investigate whether use of an immunosuppressant and the target gene-based qPCR are helpful to reduce the number of animals affected and to improve parasite detection in an immunocompetent mouse model. These results were verified by subpassage test. In the drug-suppressive test, no B. microti were observed after immunosuppressant administration or in subpassage mice in the 100 mg/kg robenidine hydrochloride (ROBH) group. The opposite results were observed in the control, 50 mg/kg ROBH, atovaquone (ATO) + azithromycin (AZM), and proguanil hydrochloride (PGH) groups. Significant differences were observed in the EIR and target gene relative values (both P0.001) between the control group and any ROBH groups. In the drug-therapeutic test, recrudescence occurred in the 50 mg/kg ROBH, ATO+AZM, and control groups. This was not observed in the 100 mg/kg ROBH group after immunosuppressant administration. Similar findings were observed in the subpassage test. This suggests that a 4-day anti-B. microti drug-suppressive test can be used in preliminary drug screening. Potentially effective drugs can be verified by immunosuppressant test in subsequent drug-therapeutic tests. Thus, a laboratory evaluation method of anti-B. microti drug efficacy was optimized, which is highly accurate and requires a short drug screening time.

Two new 1,3-benzodioxole derivatives, leucandioxoles A and B (

The Arctic fungus

Cystic echinococcosis is a globally distributed zoonotic disease, which is caused by the larval stage of Echinococcosus granulosus sensu lato. The chemotherapy of the disease is limited to the use of benzimidazoles. Recently, mefloquine and its analogues, aminoalcohol-carbazole, and some amino alcohol derivatives were reported to display inhibitory effects on parasites. Here, the activities of 130 amino alcohol compounds against E. granulosus were tested on protoscoleces and germinal cells at a concentration of 20 μg/ml over a period of three days. As a result, sixteen compounds totally were effective against both protoscoleces and germinal cells, and their IC50 and LC50 were also calculated respectively. Then effects of the most active compounds were observed on metacestodes over 14 days in vitro. Although the structure of active compounds were variable, hydroxyl and amino groups connected by two carbon atoms are held in common as the key feature of these compounds. The further investigation on metacestodes incubated with these active compounds revealed that the effects of JF16 and BTB4 were comparable to that of mefloquine and mebendazole. In addition, the ultrastructure alternations induced by these compounds on E. granulosus were confirmed by scanning electron microscopy and transmission electron microscopy observations. In conclusion, amino alcohols were a class of compounds with efficacy against E. granulosus. The most effective compounds JF16 and BTB4 indicated that their basic structure would be useful in the synthesis of new compound for the treatment of echinococcosis. However, their in vivo efficacy and toxicity need to be carefully evaluated in the future.

RNA modifications, as one of epigenetic mechanisms, are important and conserved mechanisms for maintaining the homeostasis of organisms. Little is known about RNA modifications in Echinococcus granulosus, an obligate parasite that inhabits mammals and gives rise to a huge public health and economic impact. Here, we focused on the RNA modification characteristics of E. granulosus for the first time by using mass spectrometry (UPLC-MS/MS) to qualitatively and quantitatively analyze 47 types of RNA modifications in E. granulosus total RNA. Furthermore, the E. granulosus homologs of writer enzymes preforming RNA modifications were identified, and their gene expression pattern at different developmental stages were analyzed by bioinformatics analysis. Finally, 23 types of RNA modifications were found in E. granulosus cysts total RNA, of which m1A, Ψ and m5C are the most abundant. The homologs of writer enzymes involved in these modifications were identified in the E. granulosus genome, with the dynamic gene expression during the different parasitic developmental stages. This work confirms that E. granulosus retains the conserved RNA modification mechanism during evolution, suggesting the important role of RNA modification in regulating its development and parasitic process. Moreover, the differences of amino acid sequences of RNA modification writer enzymes between parasite and host make it possible to use these enzymes as the candidate drug targets in the follow-up in-depth researches.

Eleganstone A (1), a rare diterpene possessing a 5/6/4/5 fused tetracyclic ring skeleton, along with its probable biogenetic precursor (2), one new dolabellane diterpene (3), and one known dolabellane diterpene (4), have been isolated from the marine sponge Dactylospongia elegans. As a pair of Z/E isomers, 2 can convert into 4 by the light-induced isomerization. Structure elucidations of all compounds were performed by spectroscopic analysis, ECD calculations, and comparison with the literature. These compounds were tested for their antibacterial and cytotoxic activities. Compounds 1–4 exhibited weak antibacterial activity against Escherichisa coli, Bacillus subtilis, and Staphylococcus aureus with MIC values of 32–64 μg/mL.