Individuals with inhibited immunity may develop lethal toxoplasmosis; thus, a safe and effective vaccine is urged to be developed. Toxoplasma gondii (T. gondii) a-amylase (a-AMY) is one of the enzymes responsible for starch digestion. In the present study, we first generated a ME49Da-amy mutant and discovered that loss of a-AMY robustly grew in vitro but contributed to significant virulence attenuation in vivo. Therefore, we established a mouse model to explore the protective immunity of Da-amy mutant against acute and chronic toxoplasmosis. The results indicated that the survival rates of short-term or long-term immunized mice re-infected with the tachyzoites of multiple T. gondii strains were nearly 100%. ME49Da-amy not only could provide protective immunity against tachyzoites infection but also could resist the infection of tissue cysts. Furthermore, we detected that ME49Da-amy vaccination could effectively eliminate the proliferation of parasites in mice and prevent the formation of cysts. The significant increases of Th1-type cytokines, Th2-type cytokines and specific total IgG and IgG subclasses (IgG2a and IgG1) confirmed efficiency of a combination of cellular and humoral immunity against infection. In conclusion, ME49Da-amy attenuated strain can produce strong immune responses to provide efficient protection against toxoplasmosis, which signifies that ME49Da-amy mutant may be a potential vaccine candidate.
The xerophyte Pugionium cornutum adapts to salt stress by accumulating inorganic ions (e.g., Cl − ) for osmotic adjustment and enhancing the activity of antioxidant enzymes, but the associated molecular basis remains unclear. In this study, we first found that P. cornutum could also maintain cell membrane stability due to its prominent ROS-scavenging ability and exhibits efficient carbon assimilation capacity under salt stress. Then, the candidate genes associated with the important physiological traits of the salt tolerance of P. cornutum were identified through transcriptomic analysis. The results showed that after 50 mM NaCl treatment for 6 or 24 h, multiple genes encoding proteins facilitating Cl − accumulation and NO 3 − homeostasis, as well as the transport of other major inorganic osmoticums, were significantly upregulated in roots and shoots, which should be favorable for enhancing osmotic adjustment capacity and maintaining the uptake and transport of nutrient elements; a large number of genes related to ROS-scavenging pathways were also significantly upregulated, which might be beneficial for mitigating salt-induced oxidative damage to the cells. Meanwhile, many genes encoding components of the photosynthetic electron transport pathway and carbon fixation enzymes were significantly upregulated in shoots, possibly resulting in high carbon assimilation efficiency in P. cornutum. Additionally, numerous salt-inducible transcription factor genes that probably regulate the abovementioned processes were found. This work lays a preliminary foundation for clarifying the molecular mechanism underlying the adaptation of xerophytes to harsh environments.
Toxoplasma gondii is a protozoan parasite, occurring worldwide, endangers human health and causes enormous economic losses to the Ministry of Agriculture. A safe and effective vaccination is needed to handle these problems. In addition, ideal vaccine production is a challenge in the future. In this study, we knocked out the adenylosuccinate lyase (ADSL) gene and found that the gene reduces the growth rate of T. gondii tachyzoites in vitro under standard growth conditions by plaque or replication experiments. Furthermore, mice that were immunized with tachyzoites of the ME49ΔADSL strain induced 100% protection efficacy against challenge with the type 1 strain RH, type 2 strain ME49 and type 3 strain VEG. All mice that were immunized with ME49ΔADSL had a survival rate of 100% when they were reinfected with wild-type strains, either 30 days or 70 days after immunization, and immunization was also protective against homologous infection with 50 T. gondii ME49 tissue cysts. In addition, the level of Toxoplasma-specific IgG was significantly elevated at 30 and 70 days after immunization. ME49ΔADSL induced high levels of Th1 cytokines (interferon gamma (IFN-γ), interleukin (IL)-12) at 4 weeks after immunization and spleen cell cultures from mice vaccinated for 150 days were able to produce robust INF-γ and IL-12 levels in the supernatant. The results of the present study showed that ΔADSL vaccination induced a T. gondii-specific cellular immune response against further infections. These results suggest that the ADSL-deficient vaccine can induce anti-Toxoplasma gondii humoral and cellular immune responses and has 100% immune protection against post-challenge by the type 1 strain RH, type 2 strain ME49 and type 3 strain VEG. It will be used as an excellent candidate for live vaccines and may contribute in a positive meaning to control human toxoplasmosis.
Background: Pugionium cornutum is a xerophytic plant that primarily adapts to salt stress by accumulating inorganic ions (e.g., Cl - ) for osmoregulation, improving its reactive oxygen species (ROS)-scavenging ability and maintaining high photosynthetic carbon assimilation efficiency, but the associated molecular mechanisms still remain unclear. Results : Here, we present an analysis of gene responses to salt stress based on the transcriptome of P. cornutum exposed to 50 mM NaCl treatment. The data revealed that, after NaCl treatment for 6 or 24 h, the transcript levels of multiple genes encoding proteins facilitating Cl - accumulation and NO 3 - homeostasis such as SLAH1, CLCg, CCC1, and NPF6.4, as well as the transport of other major inorganic osmoticums were significantly upregulated in roots and shoots, which should be favorable to enhancing osmotic adjustment capacity and maintaining the plant uptake and transport of nutrient elements; a large number of genes related to ROS-scavenging pathways were also significantly upregulated, which should be beneficial for mitigating salt-induced oxidative damage to the cell metabolism. Meanwhile, many genes encoding components of the photosynthetic electron transport and carbon fixation enzymes were significantly upregulated in shoots after salt treatment, possibly resulting in a high carbon assimilation efficiency in P. cornutum . Additionally, numerous salt-inducible transcription factor genes probably regulating the abovementioned processes were found. Conclusion : Candidate genes involved in salt tolerance of P. cornutum were identified, which lays a preliminary foundation for clarifying the molecular mechanism of the xerophytes adapting to harsh environments.
Background: Pugionium cornutum is a xerophytic plant that primarily adapts to salt stress by accumulating inorganic ions (e.g., Cl-) for osmoregulation, improving its reactive oxygen species (ROS)-scavenging ability and maintaining high photosynthetic carbon assimilation efficiency, but the associated molecular mechanisms still remain unclear. Results: Here, we present an analysis of gene responses to salt stress based on the transcriptome of P. cornutum exposed to 50 mM NaCl treatment. The data revealed that, after NaCl treatment for 6 or 24 h, the transcript levels of multiple genes encoding proteins facilitating Cl- accumulation and NO3- homeostasis such as SLAH1, CLCg, CCC1, and NPF6.4, as well as the transport of other major inorganic osmoticums were significantly upregulated in roots and shoots, which should be favorable to enhancing osmotic adjustment capacity and maintaining the plant uptake and transport of nutrient elements; a large number of genes related to ROS-scavenging pathways were also significantly upregulated, which should be beneficial for mitigating salt-induced oxidative damage to the cell metabolism. Meanwhile, many genes encoding components of the photosynthetic electron transport and carbon fixation enzymes were significantly upregulated in shoots after salt treatment, possibly resulting in a high carbon assimilation efficiency in P. cornutum. Additionally, numerous salt-inducible transcription factor genes probably regulating the abovementioned processes were found. Conclusion: Candidate genes involved in salt tolerance of P. cornutum were identified, which lays a preliminary foundation for clarifying the molecular mechanism of the xerophytes adapting to harsh environments.
Carbapenem-resistant Enterobacteriaceae have emerged as a major threat to modern medicine, and the spread of carbapenem-resistant Enterobacteriaceae is a clinical and public health problem. Gastrointestinal colonization by potential pathogens is always a prerequisite for the development of translocated infections, and there is a growing need to assess clinical risk factors and microbiological and intestinal characteristics to prevent the development of clinical infection by carbapenem-resistant Enterobacteriaceae .
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