Effects of over-expression of allene oxide cyclase on camptothecin production by cell cultures of Camptotheca acuminata

Camptothecin (CPT) is an anticancer and antiviral monoterpene-derived indole alkaloid which can be induced by plant hormone, jasmonates. To improve the production of the pharmaceuticals, the jasmonate biosynthesis related gene allene oxide cyclase from Camptotheca acuminate was transferred back into C. acuminate using the method of Agrobacterium-mediated genetic transformation and over expressed. The results of high performance liquid chromatography (HPLC) analysis indicated that the camptothecin content of transgenic callus was higher than that of non-transgenic callus. The highest camptothecin content in transgenic callus was 3.9310 mg/g DW. However, camptothecin content in both transgenic and non-transgenic calli significantly decreased after further extrinsic methyl-jasmonate’s (MeJA's) induction, whereas the content of CPT in transgenic callus was still higher than in non-transgenic one. All the results indicate that endogenic jasmonate's accumulation may be promoted after allene oxide cyclase gene was transformed into C. acuminate and over expressed. In this way, jasmonates can affect second metabolism pathway genes' expression and then the camptothecin content improved. Inexpectantly, the mechanism of extrinsic jasmonate to secondary metabolism of C. acuminate was different from that of endogenic jasmonates.Key words: Agrobacterium tumefaciens, Allene oxide cyclase, Camptotheca acuminata, camptothecin, methyl-jasmonates, transformation

Impulsive alignment of 4He-CH3I: a theoretical study

We simulate the non-adiabatic laser alignment of the weakly bound 4He-CH3I complex based on a quantum mechanical wave packet calculation for a model He-CH3I interaction potential. Two different regimes are found depending on the laser intensity. At intensities typical of non-adiabatic alignment experiments, the rotational dynamics resembles that of the isolated molecule. This is attributed to the fact that after the initial prompt alignment peak the complex rapidly dissociates. The subsequent revival pattern is due to the free rotation of the molecule detached from the helium atom. It is superimposed to a flat background corresponding to ∼20% of the wave packet which remains bound, containing lower rotational excitation. At lower intensities, dissociation is avoided but the rotational excitation is not high enough to provide an efficient alignment and a broad non-regular structure is observed. Besides, the interaction of the He atom with the molecule quenches any possible alignment. These interpretations are based on the calculation of different observables related to the rotational motion. We compare our findings with recent experimental and theoretical results of non-adiabatic alignment of linear molecules solvated in helium nanodroplets or weakly interacting with one helium atom

The effects of intro-oral parathyroid hormone on the healing of tooth extraction socket: an experimental study on hyperglycemic rats

Objective: To investigate the effects of intro-oral injection of parathyroid hormone (PTH) on tooth extraction wound healing in hyperglycemic rats. Methodology: 60 male Sprague-Dawley rats were randomly divided into the normal group (n=30) and DM group (n=30). Type 1 diabetes mellitus (DM) was induced by streptozotocin. After extracting the left first molar of all rats, each group was further divided into 3 subgroups (n=10 per subgroup), receiving the administration of intermittent PTH, continuous PTH and saline (control), respectively. The intermittent-PTH group received intra-oral injection of PTH three times per week for two weeks. A thermosensitive controlled-release hydrogel was synthesized for continuous-PTH administration. The serum chemistry was determined to evaluate the systemic condition. All animals were sacrificed after 14 days. Micro-computed tomography (Micro-CT) and histological analyses were used to evaluate the healing of extraction sockets. Results: The level of serum glucose in the DM groups was significantly higher than that in the non-DM groups (p<0.05); the level of serum calcium was similar in all groups (p>0.05). Micro-CT analysis showed that the DM group had a significantly lower alveolar bone trabecular number (Tb.N) and higher trabecular separation (Tb.Sp) than the normal group (p<0.05). The histological analyses showed that no significant difference in the amount of new bone (hard tissue) formation was found between the PTH and non-PTH groups (p>0.05). Conclusions: Bone formation in the extraction socket of the type 1 diabetic rats was reduced. PTH did not improve the healing of hard and soft tissues. The different PTH administration regimes (continuous vs. intermittent) had similar effect on tissue healing. These results demonstrated that the metabolic characteristics of the hyperglycemic rats produced a condition that was unable to respond to PTH treatment