[Effects of phosphorus fertilization on leaf area index, biomass accumulation and allocation, and phosphorus use efficiency of intercropped maize].

A 2-year field experiment was conducted in 2011 and 2012 to investigate the effects of phosphorus (P) fertilization on the leaf area index (LAI), dry matter accumulation (DMA), and P use efficiency (PUE) of maize in wheat/maize/soybean intercropping system. Five P fertilization rates were installed, i.e., 0, 45, 90, 135, and 180 kg P2O5 x hm(-2) for wheat, marked as WP0, WP1, WP2, WP3, and WP4, respectively, and 0, 37.5, 75, 112.5, and 150 kg P2O5 x hm(-2) for maize, marked as MP0, MP1, MP2, MP3, and MP4, respectively. During the coexisted growth periods of wheat and maize, P fertilization increased the LAI, leaf area duration (LAD), and stem and leaf DMA of maize significantly. After the jointing stage of maize, the maize LAI, LAD, DMA, and crop growth rate (CGR) all decreased after an initial increase with the increasing P rate, with the maximum growth in treatment MP2 or MP3. During the reproductive stage of maize, the maize dry mass translocation from vegetative to reproductive organ increased with increasing P fertilization rate, and the grain yield of both maize and whole cropping system increased firstly and decreased then, with the maximum grain yield of maize and whole cropping system being 6588 and 11955 kg x hm(-2) in treatment P3, respectively. The P apparent recovery efficiency of maize was the highest (26.3%) in treatment MP2, being 82.6%, 38.4%, and 152.9% higher than that in MP1 (14.4%), MP3 (19.0%), and MP4 (10.4%), respectively. In sum, for the wheat/maize/soybean intercropping system, applying appropriate amount of P fertilizer could promote maize growth, alleviate the impact of wheat on maize, and consequently, increase the P apparent recovery efficiency of maize. In this study, the appropriate P fertilization rate was 75-112.5 kg P2O5 x hm(-2).

Distally based saphenous nerve-great saphenous veno-fasciocutaneous compound flap with nutrient vessels: microdissection and clinical application.

Improvements were made by us in several distally based pedicled flaps of the nutrient vessels of the saphenous nerve with lower rotation points. However, these flaps are still insufficient for trauma complicated by bone defects. Accordingly, we conducted a systematic study of the anatomic theory on distally based pedicled compound flaps of the nutrient vessels of the saphenous nerve and great saphenous vein with 30 lower limbs of adult cadavers injected with red gelatin through the femoral artery. It is found that the nutrient vessels of the saphenous nerve-great saphenous vein consist of arteria saphena, fascial cutaneous branches of the inferior medial genicular artery intermuscular spatium branches of the posterior tibial artery, osteocutaneous perforators, superior ankle perforators, medial anterior malleolus perforators, and fascial perforators of the ankle tunnel region. Musculocutaneous perforators of the interior gastrocnemius muscle also enter the nutrient vessels of cutaneous nerve-superficial vein. From May 2004 to February 2007, 23 cases of skin flaps for treating defective and infectious wound, 10 cases of musculocutaneous flaps for treating ulcus in the lower segment of the leg, medullitis, and exposure of bone, 3 cases for medial calcaneus medullitis, 7 cases of skeletal flaps for treating tibial defects and nonunion of calcaneal bone. In 2-15-month follow-ups all cases presented with survived flaps, and healed surfaces of the wound and the osteomyelitis. For cases of bone nonunion, it showed that the nonunion healed after 18 weeks, with recovery of work ability after year. Three types of the distally based pedicled flaps or compound flaps of vessels of different perforating branches can be designed for repairing tissue defects caused by trauma, such as bone defects in the distal leg, nonunion, large necrotic space as well as traumatic surface of the foot and ankle.

[Construction of a multi-copy Pichia expression vector and expression of human brain-derived neurotrophic factor in Pichia pastoris].

A pPICZ alpha1 vector was reconstructed with pPICZ alpha vector and PCR product of His4-Kan sequence from pPIC9K vector. The sequence encoding human brain-derived neurotrophic factor (hBDNF) was inserted into pPICZ alpha1. The expression vectors carrying 1, 2, 3, 6 copies of expression cassettes were constructed and transformed into Pichia pastoris GS115 respectively. The transformants were screened with G418/Zeocin and induced by 0.5% methanol, and the results of SDS-PAGE confirmed that the expression protein was about 14 kD and the percentage of the protein was about 20% of the total secreted protein. ELISA and Western blot analysis demonstrated that the protein could be specifically combined with chicken antibodies to human-BDNF.

[Design and preparation of the multimeric self-cleavable hammerhead ribozyme targeting apple scar skid viroid and its activity detection in vitro].

A self-cleaving hammerhead ribozyme gene containing a 14nt target sequence of ASSVd at the 3' end of hammerhead ribozyme was synthesized, amplified and cloned at the Xho I-Hind III site of pGEM7Zf(+). The ends produced by Xho I or Sal I can link together, thus the recognition sites of both enzymes vanish and can't be cut by either one. We used this property to get the recombinant plasmid bearing 2, 4, 6, 8, 10 and 12 copies of self-cleavable ribozyme respectively after successively sub-cloning five times. Linearized recombinat plasmid model catalyzed by T7 RNA polymerase was transcribed in vitro. The multimeric ribozyme molecules efficiently self-cleaved via cis-acting to release many ribozyme molecules It indicates that the concentration of ribozyme transcripts has been enhanced during transcription. Trans-cleavage reaction was carried out by incubating monomeric and multimeric ribozymes with same mol concentration and 32P labeled target ASSVd. Both ribozymes and target transcripts were mixed in 1:1 ratio. Autoradiograms showed the transcripts of multimeric ribozyme were substantially more effective against the ASSVd target RNA than the monomeric ribozymes. We confer that the multimeric self-clevable ribozyme is likely to provide more valuable application in vivo.