Downregulation of a CT10 regulator of kinase (Crk) promotes the formation of diapause embryos in the brine shrimp Artemia.

To survive under harsh environments, embryonic development of Artemia was arrested at the gastrula stage and released as the diapause embryo. Cell cycle and metabolism were highly suppressed in this state of quiescence. However, cellular mechanisms underlying diapause remain largely unclear. In this study, we found that the expression level of a CT10 regulator of kinase-encoding gene (Ar-Crk) in diapause embryos was significantly lower than non-diapause embryos at the early embryogenetic stage of Artemia. Knockdown of Ar-Crk by RNA interference induced formation of diapause embryos, while the control group produced nauplii. Western blot analysis and metabolic assays revealed that the diapause embryos produced by Ar-Crk-knocked-down Artemia had similar characteristics of diapause markers, arrested cell cycle, and suppressed metabolism with those diapause embryos produced by natural oviparous Artemia. Transcriptomic analysis of Artemia embryos revealed knockdown of Ar-Crk induced downregulation of the aurora kinase A (AURKA) signaling pathway, as well as energetic and biomolecular metabolisms. Taken together, we proposed that Ar-Crk is a crucial factor in determining the process of diapause in Artemia. Our results provide insight into the functions of Crk in fundamental regulations such as cellular quiescence.

A cytological revisit on parthenogenetic Artemia and the deficiency of a meiosis-specific recombinase DMC1 in the possible transition from bisexuality to parthenogenesis.

Although parthenogenesis is widespread in nature and known to have close relationships with bisexuality, the transitional mechanism is poorly understood. Artemia is an ideal model to address this issue because bisexuality and "contagious" obligate parthenogenesis independently exist in its congeneric members. In the present study, we first performed chromosome spreading and immunofluorescence to compare meiotic processes of Artemia adopting two distinct reproductive ways. The results showed that, unlike conventional meiosis in bisexual Artemia, meiosis II in parthenogenic Artemia is entirely absent and anaphase I is followed by a single mitosis-like equational division. Interspecific comparative transcriptomics showed that two central molecules in homologous recombination (HR), Dmc1 and Rad51, exhibited significantly higher expression in bisexual versus parthenogenetic Artemia. qRT-PCR indicated that the expression of both genes peaked at the early oogenesis and gradually decreased afterward. Knocking-down by RNAi of Dmc1 in unfertilized females of bisexual Artemia resulted in a severe deficiency of homologous chromosome pairing and produced univalents at the middle oogenesis stage, which was similar to that of parthenogenic Artemia, while in contrast, silencing Rad51 led to no significant chromosome morphological change. Our results indicated that Dmc1 is vital for HR in bisexual Artemia, and the deficiency of Dmc1 may be correlated with or even possibly one of core factors in the transition from bisexuality to parthenogenesis.

Identification and characterization of the Doublesex gene and its mRNA isoforms in the brine shrimp Artemia franciscana.

Doublesex (DSX) proteins are members of the Doublesex/mab-3-related (DMRT) protein family and play crucial roles in sex determination and differentiation among the animal kingdom. In the present study, we identified two Doublesex (Dsx)-like mRNA isoforms in the brine shrimp Artemia franciscana (Kellogg 1906), which are generated by the combination of alternative promoters, alternative splicing and alternative polyadenylation. The two transcripts exhibited sex-biased enrichment, which we termed AfrDsxM and AfrDsxF. They share a common region which encodes an identical N-terminal DNA-binding (DM) domain. RT-qPCR analyses showed that AfrDsxM is dominantly expressed in male Artemia while AfrDsxF is specifically expressed in females. Expression levels of both isoforms increased along with the developmental stages of their respective sexes. RNA interference with dsRNA showed that the knockdown of AfrDsxM in male larvae led to the appearance of female traits including an ovary-like structure in the original male reproductive system and an elevated expression of vitellogenin. However, silencing of AfrDsxF induced no clear phenotypic change in female Artemia. These results indicated that the male AfrDSXM may act as inhibiting regulator upon the default female developmental mode in Artemia. Furthermore, electrophoretic mobility shift assay analyses revealed that the unique DM domain of AfrDSXs can specifically bind to promoter segments of potential downstream target genes like AfrVtg. These data show that AfrDSXs play crucial roles in regulating sexual development in Artemia, and further provide insight into the evolution of sex determination/differentiation in sexual organisms.

[Comparison of the distribution of breviscapine in the brain by different administration routes].

By comparing the drug distribution of breviscapine administered intranasally, orally and intrgvenous injected in rats' brain. After 0.4 mg x kg(-1) breviscapine was given by tail vein, intranasal and gastric perfusion administration to SD rats, cerebrospinal fluid was obtained by erebellomedllery cisternal puncture at different times. 125I labeling was used to determine the drug content of cerebrospinal fluid, cerebrum, cerebellum, medulla oblongata, olfactory region, olfactory bulb and blood in rats. AUCs were calculated by trapezoidal rule. The results showed that AUCs(0-240 min) (microg x min x g(-1)) of brain tissues were 11.686 +/- 1.919, 5.676 +/- 1.025, 7.989 +/- 0.925, 7.956 +/- 1.159, 17.465 +/- 2.136, 24.2 +/- 2.906 and 78.51 +/- 12.05, respectively, in the intranasal administration group; while those in the tail vein administration groups were 6.79 +/- 0.661, 6.251 +/- 0.40, 10.805 +/- 1.161, 9.146 +/- 1.04, 9.892 +/- 1.532, 7.871 +/- 0.842 and 173.91 +/- 10.02; and oral administration group were 0.868 +/- 0.167, 1.708 +/- 0.266, 2.867 +/- 0.725, 2.067 +/- 0.313, 1.361 +/- 0.308, 1.206 +/- 0.255 and 45.2 +/- 7.52, respectively. AUCs(0-240 min) of the brain tissues after oral, tail vein and intranasal administration were 22.29%, 29.18%, 95.49% of that of blood, respectively, it means that the absorption rate and drug distribution in the brain tissues after intranasal administration were higher than those of oral and tail vein administration. It is worth to investigate further the pharmacodynamic relationship.

[Evaluation of targeting property for Kuikang colon targeted pellets].

OBJECTIVE: To evaluate colon targeting characteristic of Kuikang colon targeted pellets (KCP) with determination of residual baicalin and baicalein concentration in gastrointestinal tract (GIT). METHOD: The baicalin and baicalein were assayed by HPLC. The recovery differences of the drug between KCP and conventional pellets from GIT were investigated, three and six hours after administration. RESULT: The baicalin recovery of KCP (70%) from rat GIT was higher than that of CP (about 20%). Most of KCP were intact at 3 h after oral administration, and distributed in lower ileum. It indicated that release site of KCP was in lower ileum and colon. Six hours later, a small amount of baicalin was recovered in intestime, which showed that the release of baicalin from KCP was complete. CONCLUSION: The determination of residual baicalin in rat GIT was feasibility for evaluating KCP. The result confirmed KCP of colon targeting property.

[Preliminary study on sea cucumber saponin-nobiliside A liposome and its hemolytic activity].

Nobiliside A (Nob A) liposomes were prepared. Its assay method of content and encapsulation efficiency (EE) were established, and hemolytic activity with Nob A solution in vivo and in vitro were compared. Preparative method, phospholipid content, ratio of phospholipid to cholesterol and ratio of drug to lipids were optimized by single factor exploration. According to the optimized results, 3 batches of Nob A liposomes were prepared, then high performance liquid chromatography coupled with evaporative light scattering detector (HPLC-ELSD) method was used to determine the content of Nob A and minicolumn centrifugation method to determine EE, transmission electron microscope was used to detect the morphology and laser scatter analysis to evaluate particle sizes of the liposomes. The hemolytic activity was studied both in vivo and in vitro. The results indicated that HPLC-ELSD method and minicolumn centrifugation method used in this study are simple, applicable and accurate for the determination of the content and EE of Nob A liposome respectively . Nob A liposomes have a high EE with spherical shape and uniform size by using the film ultrasonication technique. When the ratio of phospholipid to cholesterol was 2:1 and the ratio of Nob A to lipids was 1:40, the mean EE of Nob A liposomes was 95.7% and the mean diameter was 87.6 nm. Liposomes inhibited the hemolytic activity of Nob A in vivo and in vitro sharply. As for its low hemolytic activity in vivo and in vitro, Nob A liposomes are optimistic to be used by intravenous injection.

[Pharmacokinetics of pueraria for intranasal on spray in rabbits].

OBJECTIVE: To explore pharmacokinetic features of puerarin in pueraria spray and calculate pharmacokinetic parameters according to puerarin of drug-time curve in rabbits. METHODS: The concentration of puerarin in plamsa was determined by HPLC. The methanol was used to sediment protine. The 3P87 program was used to calculate the pharmacokinetic parameters. RESULTS: The vivo course of pueraria in spray could be described by the two compartment model. The main pharmacokinetic parameters of Pueraria spray were: t(l/2(beta)) =0.93 h, CL =44.23 mg x L(-1), AUC = 16.28 mg x h x L(-1), Cmax =5.9 mg x L(-1) and tmax = 0.975 h. CONCLUSION: The study will provide some scientific basises for the quality evaluation and pharmaceutics reformation of pueraria for intranasal.

[Study on purification of Radix Paeoniae Alba by HPD100 macroporous resin].

OBJECTIVE: To set up the method for purification of paeoniflorin by HPD100 macroporous resin. METHODS: With the adsorption ration and desorption rate of paeoniflorin as the evaluating quotas, the single factor test, orhogonal experimental designs and variance analysis were applied to optimize the manipulation parameters of macrporous resin. RESULTS: The HPD100 had the best adsorbive and separative properties to paeoniflorin. The applicable technology was as follows: the sample concentration was 0.5 g/ml, the maximum capacity for medicinal materials was 10 g/g, the current velocit was 2 BV/h, the eluting reagent was 30% ethanol (4 times the volume of bottle). CONCLUSION: HPD100 resin can be used in purify of Radix Paeoniae Alba successfully. The purity of paeoniflorin was above 30%.