Evaluation of in vitro antileishmanial efficacy of cyclosporin A and its non-immunosuppressive derivative, dihydrocyclosporin A.

BACKGROUND: New therapeutic drugs are urgently needed against visceral leishmaniasis because current drugs, such as pentavalent antimonials and miltefosine, produce severe side effects and development of resistance. Whether cyclosporine A (CsA) and its derivatives can be used as therapeutic drugs for visceral leishmaniasis has been controversial for many years. METHODS: In this study, we evaluated the efficacy of CsA and its derivative, dihydrocyclosporin A (DHCsA-d), against promastigotes and intracellular amastigotes of Leishmania donovani. Sodium stibogluconate (SSG) was used as a positive control. RESULTS: Our results showed that DHCsA-d was able to inhibit the proliferation of L. donovani promastigotes (IC50: 21.24 µM and 12.14 µM at 24 h and 48 h, respectively) and intracellular amastigotes (IC50: 5.23 µM and 4.84 µM at 24 and 48 h, respectively) in vitro, but CsA treatment increased the number of amastigotes in host cells. Both DHCsA-d and CsA caused several alterations in the morphology and ultrastructure of L. donovani, especially in the mitochondria. However, DHCsA-d showed high cytotoxicity towards cells of the mouse macrophage cell line RAW264.7, with CC50 values of 7.98 µM (24 h) and 6.65 µM (48 h). Moreover, DHCsA-d could increase IL-12, TNF-α and IFN-γ production and decrease the levels of IL-10, IL-4, NO and H2O2 in infected macrophages. On the contrary, CsA decreased IL-12, TNF-α, and IFN-γ production and increased the levels of IL-10, IL-4, NO and H2O2 in infected macrophages. The expression of L. donovani cyclophilin A (LdCyPA) in promastigotes and intracellular amastigotes and the expression of cyclophilin A (CyPA) in RAW 264.7 cells were found to be significantly downregulated in the CsA-treated group compared to those in the untreated group. However, no significant changes in LdCyPA and CyPA levels were found after DHCsA-d or SSG treatment. CONCLUSIONS: Our findings initially resolved the dispute regarding the efficacy of CsA and DHCsA-d for visceral leishmaniasis treatment. CsA showed no significant inhibitory effect on intracellular amastigotes. DHCsA-d significantly inhibited promastigotes and intracellular amastigotes, but it was highly cytotoxic. Therefore, CsA and DHCsA-d are not recommended as antileishmanial drugs.

[Pollutant Removal Performance and Membrane Fouling Characteristics in Marine Aquaculture Wastewater Treatment by a Microalgae Membrane Reactor].

In order to treat mariculture wastewater, the pollutant removal performance and membrane fouling characteristics of a microalgae membrane reactor were investigated using Platymonas helgolandica tsingtaoensis. After 60 days of operation, the total nitrogen (TN) and total phosphorus (TP) removal efficiency of the reactor were 73.6% and 77.9%, respectively, and the removal rates of TN and TP reached 15 g·(m3·d)-1 and 2.8 g·(m3·d)-1. The microalgae in the reactor could be enriched rapidly, with a maximum growth rate of 53.3 mg·(L·d)-1 and a maximum biomass of 1.4 g·L-1. The microalgae in the reactor were harvested on day 18 and day 36; harvesting did not affect the nitrogen and phosphorus removal efficiency of the reactor. To some extent, the membrane fouling phenomenon was alleviated. The increase in the microalgae biomass would significantly increase the pollutant content of the membrane. The three-dimensional excitation-emission matrix (EEM) spectra results confirmed that tryptophan-like substances and aromatic proteins had a significant effect on membrane fouling.

Direct and Indirect Inhibition Effects of Resveratrol against Toxoplasma gondii Tachyzoites In Vitro.

Toxoplasma gondii is one of the most widespread obligatory parasitic protozoa and infects nearly all warm-blooded animals, leading to toxoplasmosis. The therapeutic drugs currently administered, like the combination of pyrimethamine and sulfadiazine, show high rates of toxic side effects, and drug resistance is encountered in some cases. Resveratrol is a natural plant extract with multiple functions, such as antibacterial, anticancer, and antiparasite activities. In this study, we evaluated the inhibitory effects of resveratrol on tachyzoites of the Toxoplasma gondii RH strain extracellularly and intracellularly. We demonstrate that resveratrol possesses direct antitoxoplasma activity by reducing the population of extracellularly grown tachyzoites, probably by disturbing the redox homeostasis of the parasites. Moreover, resveratrol was also able to release the burden of cellular stress, promote apoptosis, and maintain the autophagic status of macrophages, which turned out to be regulated by intracellular parasites, thereby functioning indirectly in eliminating T. gondii In conclusion, resveratrol has both direct and indirect antitoxoplasma effects against RH tachyzoites and may possess the potential to be further evaluated and employed for toxoplasmosis treatment.

[Study on high efficiency tissue culture of mature seeds of rice (JiaHe-ZaoZhan)].

In order to improve the embryogenic callus induction rate and the regeneration rate of JiaHe-ZaoZhan rice, the influence of different factors were investigated, media with different hormones were used. Induction medium was supplemented with 1.5 mg/L 2,4-D + 3 mg/L NAA + 0.1 mg/L KT + 1 mg/L phytic acid + 20 mg/L PAA. Embryogenic call were treated under the condition of 25 degrees C before transferring to regeneration medium, the regeneration medium contained 0.5 mg/L 6-BA + 3 mg/L NAA + 0.5 mg/L KT + 1 mg/L phytic acid. The experiment results indicated that the hormone treatments had certain effects on the callus induction. Under the optimal medium, culture condition and the hormone treatments, the embryogenic callus induction could reach over 95%, and dry treatment of embryogenic callus had been found to increase the frequency of plant regeneration, significantly the plant regeneration rate could reach over 80%. Transplanted into pots, the young plants grew well. Then a experimental system with stability and high regenerating efficiency has been established for the mature seeds of rice (JiaHe-ZaoZhan).