SP-9

To observe the effect of electroacupuncture(EA) at "Zusanli"(ST36), "Yinlingquan" (SP9) or "Yingu"(KI10) on the expression of 5-hydroxytryptamine type 7 receptor (5-HT7R) in the gastric antrum and colon tissues in functional diarrhea (FD) model rats, so as to explore its mechanisms underlying improving FD.

Forty male SD rats were randomly divided into control, model, ST36, SP9 and KI10 groups，with 8 rats in each group. The FD model was established by combined administration of restriction (four-limbs' banding) + abdominal cold stimulation + feeding every other day, for 14 days. EA (2 Hz, 0.5 mA) was applied to bilateral ST36 or bilateral SP9 or bilateral KI10 in the 3 corresponding groups for 30 min, once a day for 7 days after successful modeling. Rats of the control group received restriction only. The fecal water content was calculated and the stool form score was given according to the Bristol's methods. The gastric residual rate (GRR) and small intestine propulsion rate (SIPR) were determined to assess the motility of the gastrointestinal tract. Immunohistochemical and real-time fluorescent quantitative PCR were used to detect the expression of 5-HT7R protein and mRNA of the gastric antrum and colon tissues, respectively.

Compared with the control group, the fecal water content, the stool form score, the SIPR and the expression levels of 5-HT7R protein and 5-HT7R mRNA were significantly increased (P<0.01,P<0.05) and the GRR was considerably decreased in the model group (P<0.01). The fecal water content, stool form score and SIPR, and expression level of 5-HT7R protein and mRNA in the gastric antrum and colon were significantly lower in both the ST36 and SP9 groups (not in the KI10 group) than in the model group (P<0.01, P<0.05), but the GRR was significantly higher in the ST36 and SP9 groups (not in the KI10 group) than in the model group (P<0.01). The effects of both ST36 and SP9 were significantly superior to those of KI10 in improving all the indexes mentioned above （except SIPR and the mRNA level of 5-HT7R in the colon in SP9 group）(P<0.01, P<0.05). No significant differences were found between the ST36 and SP9 groups in lowering the levels of fecal water content, stool form score, SIPR, and the expression of 5-HT7R protein and mRNA, as well as in up-regulating GRR (P>0.05).

EA of ST36 and SP9 can improve the motility of gastrointestinal tract in FD rats, which may be related to its functions in down-regulating the expression of 5-HT7R protein and mRNA in gastric antrum and colon tissues. The effects of ST36 and SP9 were obviously better than those of KI10 in ameliorating the gastric and intestinal motility (except GRR) and in lowering the expression of 5-HT7R protein and mRNA.

Several actinomycetes strains were isolated from different marine sponges collected from the Red Sea shore in Egypt. The efficiency of their crude extracts to inhibit histone deacetylase (HDAC) enzyme was investigated in the nuclear extract of Hela cell line. The crude extract corresponding to Streptomyces sp. SP9 isolated from the marine sponge Pseudoceratina arabica showed a promising HDAC inhibitory activity with 64 and 81% at 50 and 100 µg/ml, respectively. The strain was identified as Streptomyces sp. by phylogenetic analyses based on its 16S rRNA gene sequence. The major compounds of Streptomyces sp. SP9 were isolated and purified by different chromatographic methods. The chemical structure of the isolated compounds was identified on the basis of their spectroscopic data including mass, ¹H and ¹³C NMR, and by comparison with those of authenticated samples. Structures of compounds 1 and 2 were established as heliomycin and tetracenomycin D, respectively. These compounds exhibited HDAC inhibitory activities with IC₅₀ values of 29.8 ± 0.04 µg/ml for heliomycin (1) and 10.9 ± 0.02 µg/ml for tetracenomycin D (2). A computational docking study for compounds 1 and 2 against HDAC1, HDAC2, and HDAC3 was performed to formulate a hypothetical mechanism by which the tested compounds inhibit HDAC. Tetracenomycin D (2) showed a good binding interactions with HDAC2 (- 5.230 kcal/mol) and HDAC3 (- 6.361 kcal/mol).