Genetic characterizations of Cryptosporidium spp. from children with or without diarrhea in Wenzhou, China: high probability of zoonotic transmission.

BACKGROUND: Cryptosporidium is a highly pathogenic parasite responsible for diarrhea in children worldwide. Here, the epidemiological status and genetic characteristics of Cryptosporidium in children with or without diarrhea were investigated with tracking of potential sources in Wenzhou City, China. METHODS: A total of 1032 children were recruited, 684 of whom had diarrhea and 348 without, from Yuying Children's Hospital in Wenzhou, China. Samples of stool were collected from each participant, followed by extraction of DNA, genotyping, and molecular identification of Cryptosporidium species and subtypes. RESULTS: Twenty-two of the 1032 (2.1%) children were infected with Cryptosporidium spp. with 2.5% (17/684) and 1.4% (5/348) in diarrhoeic and asymptomatic children, respectively. Four Cryptosporidium species were identified, including C. parvum (68.2%; 15/22), C. felis (13.6%; 3/22), C. viatorum (9.1%; 2/22), and C. baileyi (9.1%; 2/22). Two C. parvum subtypes named IIdA19G1 (n = 14) and IInA10 (n = 1), and one each of C. felis (XIXa) and C. viatorum (XVaA3g) subtype was found as well. CONCLUSIONS: This is the first research that identified Cryptosporidium in children of Wenzhou, China, using PCR. Identification of zoonotic C. parvum, C. felis, C. viatorum, and their subtypes indicate potential cross-species transmission of Cryptosporidium between children and animals. Additionally, the presence of C. baileyi in children suggests that this species has a wider host range than previously believed and that it possesses the capacity to infect humans.

VdPT1 Encoding a Neutral Trehalase of Verticillium dahliae Is Required for Growth and Virulence of the Pathogen.

Verticillum dahliae is a soil-borne phytopathogenic fungus causing destructive Verticillium wilt disease. We previously found a trehalase-encoding gene (VdPT1) in V. dahliae being significantly up-regulated after sensing root exudates from a susceptible cotton variety. In this study, we characterized the function of VdPT1 in the growth and virulence of V. dahliae using its deletion-mutant strains. The VdPT1 deletion mutants (ΔVdPT1) displayed slow colony expansion and mycelial growth, reduced conidial production and germination rate, and decreased mycelial penetration ability and virulence on cotton, but exhibited enhanced stress resistance, suggesting that VdPT1 is involved in the growth, pathogenesis, and stress resistance of V. dahliae. Host-induced silencing of VdPT1 in cotton reduced fungal biomass and enhanced cotton resistance against V. dahliae. Comparative transcriptome analysis between wild-type and mutant identified 1480 up-regulated and 1650 down-regulated genes in the ΔVdPT1 strain. Several down-regulated genes encode plant cell wall-degrading enzymes required for full virulence of V. dahliae to cotton, and down-regulated genes related to carbon metabolism, DNA replication, and amino acid biosynthesis seemed to be responsible for the decreased growth of the ΔVdPT1 strain. In contrast, up-regulation of several genes related to glycerophospholipid metabolism in the ΔVdPT1 strain enhanced the stress resistance of the mutated strain.

Comparison of Gut Microbiota Diversity Between Captive and Wild Tokay Gecko (Gekko gecko).

Captive animals and wild animals may exhibit different characteristics due to the heterogeneity of their living environments. The gut microbiota play an important role in the digestion and absorption, energy metabolism, immune regulation, and physiological health of the host. However, information about the gut microbiota of captive and wild Gekko gecko is currently limited. To determine the difference in gut microbiota community composition, diversity, and structure between captive and wild geckos, we used the Illumina miseq platform to conduct high-throughput sequencing and bioinformatics analysis of the v3-v4 hypervariable region of 16S rRNA in 54 gecko samples. Our results showed that Proteobacteria, Firmicutes, Bacteroidetes, and Actinobacteria were the dominant gut microbiota phyla of the gecko. The dominant genera comprised mainly Pseudomonas, Burkholderia-caballeronia-paraburkholderia, Ralstonia, Romboutsia, and Bacteroides. Captive geckos had significantly higher alpha diversity and potential pathogenic bacteria than wild populations. Moreover, significant differences in beta diversity of gut microbiota were observed between two populations. Functional prediction analysis showed that the relative abundance of functional pathways of wild geckos was more higher in metabolism, genetic information processing and organismal system function than those in captive geckos. Total length significantly affected gut microbial community (R2 = 0.4527, p = 0.001) and explained 10.45% of the total variation for gut microbial community variance between two groups. These results may be related to differences in diet and living environment between two populations, suggesting that the management of captive populations should mimic wild environments to the greatest extent possible to reduce the impact on their gut microbiota.