A novel method for ginkgolide biosynthesis elucidation based on MeJA induction and differential metabolomics.

Ginkgolides from Ginkgo Biloba have significantly therapeutic effect to cardiovascular and cerebrovascular diseases. However, the biosynthetic pathway of ginkgolides has not been fully elucidated until now. As ginkgolides are synthesized in the ginkgo roots, the accumulation of ginkgolides intermediate metabolites varies greatly between roots and leaves. As Methyl jasmonate (MeJA) can effectively enhance the biosynthesis of ginkgolides, a novel method based on MeJA induction and differential metabolomics was used to screen the differentially intermediate metabolites among ginkgo leaves, roots and roots-MJ-3. Two differential intermediate metabolites (dehydroabietadienal and 1, 2, 3, 4, 4a, 9, 10, 10a-Octahydro-6-hydroxy-7-isopropyl-1, 4a-dimethyl-1-phenanthrenemethanol) were identified in ginkgo roots by UPLC-QTOF-MS. Then, a new ginkgolides biosynthetic pathway was proposed based on differential metabolomics. This study provides a novel method for the elucidation of nature product precursor and is helpful to promote the clarification of ginkgolides biosynthetic pathway.

[Changes of ion absorption, distribution and essential oil components of flowering Schizonepeta tenuifolia under salt stress].

In this paper, a pot experiment using quartz sands was conducted to study the effects of different concentrations of NaCl (0, 25, 50, 75, 100 mmol·L⁻¹) on the ion absorption, distribution and essential oil components of flowering Schizonepeta tenuifolia. The results showed that as NaCl concentration increased, Na⁺ content of root, stem, leaf and flower increased significantly, and that of the aerial parts was in a higher level than in the root. Regarding the K⁺ content, it decreased in the root but increased in stem, leaf and flower. Some changes were detected in the Ca²âº content, but not significant on the whole. The value of K⁺/Na⁺ and Ca²âº/Na⁺ reduced as a result of increasing NaCl concentrations. The content of essential oil increased under medium salt treatment (50 mmol·L⁻¹ NaCl). However, the synthesis and accumulation of essential oil was inhibited by the serious salt treatment (100 mmol·L⁻¹ NaCl). Over 98% of the essential oil components were terpenes, in which pulegone and menthone were the most two abundant compounds. Varieties of essential oil components did not change significantly under salt stress but their relative proportions did. The transformation of pulegone to menthone was enhanced and the value of pulegone/menthone based on their relative contents decreased with NaCl concentration increasing. Consequently, menthone ranked the most abundant compound by replacing pulegone. Relative content of D-limonene increased under medium and serious salt stress, and that of ß-caryophyllene only increased under mild treatments. So our research could provide references for the standard cultivation on saline soil of S. tenuifolia.

[The risk factors and preventions in keyhole minimally invasive approaches of intracranial aneurysms].

OBJECTIVE: To evaluate the risk factors and study the methods of prevention and treatment for the ruptures of aneurysms in keyhole minimally invasive approaches. METHODS: From 1999 to 2005, 115 cases of intracranial aneurysms were divided into 2 classes according to the risk factors of aneurysm rupture. Forty-three cases of lower risk underwent microsurgical procedures as keyhole approaches, including pterional approach in 20 cases, supraorbital approach in 18 cases, interhemispheric approach in 5 cases. Seventy-two cases, rest of microsurgical procedures, were performed as conventional craniotomy, including pterional approach in 31 cases, supraorbital approach in 11 cases, interhemispheric approach in 7 cases, pterional-supraorbital in 10 cases, pterional-interhemispheric in 6 cases, supraorbital-interhemispheric in 4 cases, pterional-supraorbital-interhemispheric in 3 cases. RESULTS: Six aneurysms leaked and 3 ruptured (rupture rate 7.0%) treated with keyhole approaches during operations. No one died by keyhole approaches. Eighteen aneurysms leaked and 9 ruptured (rupture rate 12.5%) treated with conventional approaches during operations. Two patients died by conventional approaches. CONCLUSIONS: Keyhole approaches as a time-saving, trauma-reducing procedure could improve the postoperative outcomes, but these approaches still exist probability of aneurysm rupture. It is possible that keyhole-bone flap becomes a limitation to deal with huge or ruptured aneurysms. And it is important to make a specially preventive strategy for aneurysm rupture.

[Surgical treatment of anterior circulation aneurysm via pterion keyhole approach].

OBJECTIVE: To investigate the feasibility of pterion keyhole approach with minimal invasion for treatment of the anterior circulation aneurysm. METHOD: Aneurysm clipping through the pterion keyhole approach was performed in patients with anterior circulation aneurysms, including 9 with posterior communication artery aneurysms, 3 with middle cerebral artery aneurysms and 6 with anterior communication artery aneurysms, who were in stages I to III according to Hunt-Hess scale. RESULT: All the aneurysms were clipped successfully. One patient with a left posterior communication artery aneurysm developed transient sensory aphasia and motor aphasia after surgery due to intraoperative aneurysm rupture. No facial paralysis occurred due to damage of the facial nerve. CONCLUSION: The pterion keyhole approach is a very useful surgical approach for treatment of anterior circulation aneurysms on the basis of cautious determination of indications and careful operation planning.

[Isolation and identification of a strain DN2 degrading nicotine].

A bacterial strain which was able to utilize nicotine as its sole carbon source was isolated from soil in which tobacco had grown at Sanming region in FUjian Province and named as DN2. Upon chemotaxonomic characterization and phylogenetic inference based 16S rDNA analysis, the strain DN2 was identified as a-proteobacteria, Ochrobactrum intermedium. For DN2 degrading nicotine, the optimal pH and temperature is 6.5, 30 degrees C respectively. It can tolerate high-concentration of nicotine up to 4000 mg/L in basal media. Using 500 mg/L nicotine as its sole carbon, the strain was able to degrade 15 mg/L of nicotine per liter per hour and reached its stationary phase in about 36 hours.

[Ultrastructural features of cultured rat cortical astrocytes with stretch-induced injury].

OBJECTIVE: To investigate the changes of ultrastructural features of cultured rat cortical astrocytes after stretch-induced injury. METHODS: Rat cortical astrocytes isolated from 1- to 2-day-old rats were cultured till confluency, and then plated in tissue culture wells with flexible silastic bottom after purification. A computer-controlled device was used to produce stretch-induced injury in the astrocytes with the imposed pressure of 50, 150, and 250 kPa respectively, followed by observation of the ultrastructural changes in the astrocytes with light and electron microscopy. RESULTS: Obvious ultrastructural destruction of the astrocytes occurred when the imposed stretch pressure was 50 kPa, and scanning electron microscopy demonstrated increased intercellular space and laceration of the cell body and its processes. Transmission electron microscopy revealed mitochondria swelling 1 h after stretch-induced injury and 6 h after the injury, vacuolar degeneration of the mitochondria occurred. Increased stretch pressure caused further decrease in the amount of glial filaments and densification of astrocytes. CONCLUSIONS: Stress, even at a relatively small scale, can cause disruption of intercellular juncture and ultrastructural change of the cultured astrocyte, which may be related with extensive brain edema after traumatic brain injury.

Association of epileptiform activity with neuronal death in the CA3 subfield of the hippocampus following focally evoked limbic seizures.

OBJECTIVE: To investigate the relationnship between epileptiform activity and cell death in the CA3 subfield of hippocampus following focally evoked limbic seizures through a quantitative study. METHODS: Wistar rats used in this study received intra-amygdaloid injection of kainic acid to induce type epileptiform activity of different duration with continuous electroencephalographic (EEG) monitoring. Terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) was used to detect apoptotic cells. The number of CA3 neurons survived and TUNEL-positive cells were counted to estimate the number of necrotic cells. RESULTS: Epileptiform activity induced necrosis in the major form of apoptosis of the cells in CA3 subfield of the hippocampus following focally evoked limbic seizures. The longer the type epileptiform activity lasted, the less neurons survived, with consequent increase in the number of both necrotic and apoptotic cells. CONCLUSION: Prolongation of type IV seizures dose-dependently causes increase in apoptotic and necrotic cells in CA3 subfield of the hippocampus.