Abnormal regulation for progesterone production in placenta with prenatal cocaine exposure in rats.

Cocaine abuse in pregnant women is currently a significant public hygiene problem and is tightly associated with elevated risk for preterm delivery. Placental steroidogenesis especially progesterone production was essential for success and maintenance of pregnancy in humans and rodents. In the present study, we determined the impact of prenatal cocaine exposure on pathways of placental progesterone synthesis in rats. Pregnant rats were treated cocaine twice daily (15 mg/kg/day) during the third trimester, and the maternal and fetal plasma progesterone and pregnenolone concentrations were detected. We also examined both the protein and mRNA expression of some key enzymes and regulators for progesterone production in placenta. Results showed that, after maternal cocaine use during pregnancy, progesterone and pregnenolone concentrations in both maternal and fetal rats were significantly decreased. Although prenatal cocaine exposure had no effects on placental 3ß-hydroxysteroid dehydrogenase type 1 (3ßHSD1) expression, protein and mRNA expression of the cholesterol side-chain cleavage enzyme (P450scc/CYP11a) in placenta was significantly inhibited. Moreover, protein and mRNA expressions of MLN64 that regulating cholesterol transport and activating protein 2γ (AP2γ/Tfap2c) that controlling P450scc/CYP11a gene expression in placenta were both decreased following maternal cocaine use in pregnancy. Collectively, this study suggested that prenatal cocaine exposure could insult the placental progesterone production in rats possibly associated with the high risk for preterm delivery.

Malus hupehensis NPR1 induces pathogenesis-related protein gene expression in transgenic tobacco.

Most commercially grown apple cultivars are susceptible to fungal diseases. Malus hupehensis has high resistance to many diseases affecting apple cultivars. Understanding innate defence mechanisms would help to develop disease-resistant apple crops. Non-expressor of pathogenesis-related genes 1 (NPR1) plays a key role in regulating salicylic acid (SA)-mediated systemic acquired resistance (SAR). MhNPR1 cDNA, corresponding to genomic DNA and its 5' flanking sequences, was isolated from M. hupehensis. Sequence analysis showed that the regulatory mechanism for oligomer-monomer transition of the MhNPR1 protein in apple might be similar to that of GmNPR1 in soybean, but different from that of AtNPR1 in Arabidopsis. No significant differences in MhNPR1 expression were found in M. hupehensis after infection with Botryosphaeria berengeriana, showing that MhNPR1 might be regulated by pathogens at the protein level, as described for Arabidopsis and grapevine. SA treatment significantly induced MhNPR1 expression in leaves, stems and roots, while methyl jasmonate (MeJA) treatment induced MhNPR1 expression in roots, but not in leaves or stems. The expression of MhNPR1 was highly increased in roots, moderately in leaves, and did not change in stems after treatment with 1-aminocyclopropane-1-carboxylic acid (ACC). SAR marker genes (MhPR1 and MhPR5) were induced by SA, MeJA and ACC in leaves, stems and roots. Overexpression of MhNPR1 significantly induced the expression of pathogenesis-related genes (NtPR1, NtPR3 and NtPR5) in transgenic tobacco plants and resistance to the fungus Botrytis cinerea, suggesting that MhNPR1 orthologues are a component of the SA defence signalling pathway and SAR is induced in M. hupehensis.

Rapid determination of transgene copy number in tobacco by competitive PCR using a pair of SSR primers.

We developed a straightforward, rapid, and inexpensive method to determine transgene copy number in tobacco. The plasmid (pSSRCopy) used for tobacco transformation contains a simple sequence repeat (SSR) locus, PT1199, which was partially deleted in the middle, a homogenous SSR locus in tobacco K326. A 168-bp segment of the cloned PT1199 was shortened to 95 bp by deleting a 73-bp internal fragment. Using a pair of SSR primers, competitive PCR was amplified from genomic DNA from transgenic tobacco harboring pSSRCopy, and the two expected bands were found. The 168-bp band (SSR-168) corresponds to endogenous PT1199 and the 95-bp band (SSR-95) comes from the integrated pSSRCopy. A single copy of a transgene can be easily distinguished from multiple copies by comparing band densities.

[Protective effect of Panax quinquefolium 20s-proto-panaxdiolsaponins on acute myocardial infarction in dogs].

OBJECTIVE: To study the protective effects of Panax quinquefolium 20s-protopanaxdiolsaponins extracted from leaves of P. quinquefolium (PQDS) on acute myocardial infarction(AMI) in dogs. METHOD: The parameters of myocardial infart size, the serum CK and LDH activity, myocardial metabolism, free radicals and coronary circulation etc were determined by using the model of ligation of LAD in the anaesthetized open-chest dogs. RESULT: In dogs treated with PQDS(in a dosage of 10 and 20 mg.kg-1 i.v. infusion), the myocardial infarct size, the activity of serum CK, LDH and the contents of serum FFA and LPO were decreased, whereas the activity of serum SOD and GSH-Px increased markedly. At the same time, myocardial blood flow was increased and coronary vascular resistance decreased significantly. CONCLUSION: PQDS has protective effect on myocardial ischemia by modifying metabolic dysfunction of FFA, inhibiting oxygen free radical mediated peroxidation of membrane lipids, enhancing endogenous antioxidase activity and increasing myocardial blood supply.