Antimicrobial peptides (AMPs) consist of a diverse group of small molecular polypeptides that widely exist in organisms and act as an important part of the innate immune system. AMPs can not only effectively kill bacteria, but also kill fungi, viruses, parasites and even tumor cells. It has been proved that antimicrobial peptides can inhibit the growth of different stages of Plasmodium protozoan and no drug tolerance has been identified so far, making it valuable as a novel anti-malaria agent. Currently, a variety of AMPs with anti-malarial activities have been successively isolated and identified. It includes the AMPs that target Plasmodium within erythrocytes such as dermaseptins and their derivatives dermaseptin S3 and dermaseptin S4, cecropin B and its derivatives SB-37 and Shiva-1, Defensin DefMT2, DefMT3 and DefMT5, etc. Those AMPs targeting the sexual stage of Plasmodium mainly include duramycin, melittin, TP10 and Vida1-Vida3. In this paper, the inhibition effects of AMPs on different developmental stages of Plasmodium and the possible mechanisms are reviewed.
CRISPR/Cas9 (clustered regularly interspaced short palindromic repeats)/(CRISPR-associated protein 9) is an efficient genome editing system for targeted gene disruption, site-specific insertion of foreign DNA, gene repair, etc., which provides an innovation platform of technology for functional analysis of parasite genes and selection of drug targets and vaccine candidates. Here, we review the mechanism of CRISPR/Cas9 and some recent findings on the use of CRISPR/Cas9 in parasite research, particularly in studies of Toxoplasma gondii, Plasmodium, Trypanosoma and Leishmania. The challenges and optimization strategies of the CRISPR/Cas9 system at the present stage are also discussed.
Objective To analyzed the genetic diversity, genetic differences between populations and differentiation time of Echinococcus granulosus and E. multilocularis of Qinghai isolates, in order to provide scientific basis for species tracing and prevention and control of Echinococcus in Qinghai Province, China. Methods For genetic analysis, 50 liver lesion samples were collected from hospitalized echinococcosis patients in the Affiliated Hospital of Qinghai University to extract genomic DNA and amplify mitochondrial dehydrogenase 1 gene (nad1). Sequence multiple alignment was performed using Clustal X v2.0 software. Geographic informatics mapping of patients’ residence was constructed using ArcGIS software. Sequence haplotype analysis was made with DnaSP v6 software. Modeltest 3.7 software and PAUP*4.0B10 software were used to calculate the minimum optimal nucleic acid evolution model. The Bayesian’s phylogenetic evolution tree was constructed with MrBayes-3.2.7 software. The differentiation time of each node in the phylogenetic tree was estimated with the Bayesian method using BEAST v2.6.3 software. Results We successfully identified 48 Echinococcus lesion samples specimen and obtained the full length of complete nad1 gene of 894 bp. Among them, 13 samples were identified as the G1 genotype of E. granulosus, and 35 samples as E. multilocularis. All the sequences showed > 99% similarity to those in GenBank. Four haplotypes were identified as H1-H4 in the two species respectively; H3 was the dominant haplotype in E. granulosus samples(10/13), which is present in Xining, Guoluo, Yushu, Haidong, Haibei and Huangnan. H2 haplotype was found dominant in E. multilocular samples (51.4%,18/35), which is present in Xining, Guoluo, Yushu, and Haidong. The phylogenetic tree showed that E. granulosus and G1 genotype clustered into one branch, and E. multilocularis and Asian strain clustered into one branch. The results of differentiation time showed that the nearest common ancestor of E. granulosus, E. multilocularis, E. vogeli and E. oligarthrus was about 5.5 Mya (95% confidence interval 4.5-6.5 Mya), and the differentiation time of E. granulosus and E. multilocularis was about 2.5 Mya (95% confidence interval 2.3-4.1 Mya). Conclusion Both human E. granulosus and E. multilocularis in Qinghai Province show high genetic diversity. E. granulosus was found of G1 genotype, with H3 as the dominant haplotype, while in E. multilocularis samles H2 is the dominant. The two speies are widely distributed throughout Qinghai Province. The two species of Echinococcus exhit closer genetic relationship and differentiation timing.
Objective To analyze the difference among antigens of Angiostrongylus cantonensis in different developmental stages and identify dominant diagnostic antigen for angiostrongyliasis. Methods Antigens of A.cantonensis in different developmental stages were analyzed by SDS-PAGE and immunoblot. Results The protein bands of all developmental stages were similar on SDS-PAGE. The Mr 40 000 , 50 000 , 66 000 and 80 000 antigens reacted not only with the sera of rats infected by A.cantonensis but also with the sera of normal rats. The Mr 104 000 antigen could be discerned by sera of rats infected with A.cantonensis for 2 weeks. The Mr 32 000 antigen could be recognized by sera of rats 2 weeks after infection, and the reaction became stronger with the infection continued. Conclusion The Mr 40 000 , 50 000 , 66 000 and 80 000 antigens might result in the unspecific reaction in the immunodiagnosis of angiostrongyliasis using the crude antigen of A.cantonensis. The Mr 104 000 of larva, Mr 33 000 of adult females and Mr 32 000 of the worms might be used as candidate antigens in early diagnosis and epidemiological survey of angiostrongyliasis.