二氮嗪在长时程心脏低温保存中的作用

延长心脏的体外有效保存时间对临床心脏移植具有重要意义。本文旨在研究线粒体ATP敏感性钾通道开放剂二氮嗪(diazoxide,DE)在离体大鼠心脏长时程低温保存中的作用。SD大鼠随机分成5组,包括对照组(单纯Celsior保存液),DE组(Celsior液中含15、30或45μmol／L的DE)和DE 5-HD组[Celsior液中含30μmol／L的DE和100μmol／L的5-羟基葵酸盐(5-hydroxydecanoate,5-HD)]。利用Langendorff离体鼠心灌注法,观察心脏在4℃条件下保存10h后,复灌期血流动力学恢复、冠脉流出液中心肌酶漏出量及心肌水含量变化,并做心肌超微结构检查。结果显示：与对照组比较,DE处理后,复灌期的左心室舒张末期压力明显降低,心率、左心室发展压、左心室压力变化率、冠脉流出量等的恢复率在多个复灌时间点上优于对照组,且能显著减少复灌过程中心肌酶(乳酸脱氢酶、磷酸肌酸激酶及谷草转氨酶)的漏出量,降低心肌水含量;其中30和45μmol／LDE组的保护作用优于15μmol／LDE组;电镜结果显示DE对长时程低温保存心脏的超微结构有较好的保护作用。DE的上述作用可被线粒体ATP敏感性钾通道的特异性阻断剂5-HD所取消。以上结果提示：DE可通过激活线粒体ATP敏感性钾通道显著改善离体大鼠心脏长时程低温保存效果。     

Use of asymmetric somatic hybridization for transfer of the bacterial blight resistance trait from Oryza meyeriana L. to O. sativa L. ssp. japonica

Bacterial blight is one of the major diseases affecting rice productivity. To improve the resistance of cultivated rice to bacterial blight, we introduced a bacterial blight resistance trait from Oryza meyeriana, a wild rice species, into an elite japonica rice cultivar (Dalixiang) using asymmetric somatic hybridization. One hundred and thirty-two independent lines were regenerated. The hybrid plants possessed several morphological features of the donor species, O. meyeriana. Random amplified polymorphic DNA analysis revealed that hybrid plants exhibited banding patterns derived from their parental genotypes. For the majority of the hybrids, resistance to bacterial blight pathogens was intermediate to that observed for O. meyeriana and O. sativa (cv. Dalixiang). Four of the hybrid lines exhibited a high bacterial blight resistance, but it was less than that observed for O. meyeriana. These results demonstrate that O. meyeriana can be used as a good genetic source for improving bacterial blight resistance in commercial rice cultivars through asymmetric somatic hybridization.Abbreviations 2,4-D: 2,4-Dichlorophenoxyacetic acid - IOA: Iodoacetamide - NAA: -Naphthaleneacetic acid - PEG: Polyethylene glycol Communicated by P. Lakshmanan     

The serratus anterior subslip: anatomy and implications for facial and hand reanimation

The ideal donor muscle for facial and hand reanimation has yet to be found. Donor muscles commonly used today, such as the gracilis and pectoralis minor, are limited by bulkiness and the number of force vectors they can provide. In the authors' study of 50 fresh cadaver serratus anterior muscles, they further describe neurovascular anatomy of the muscle slip (i.e., the portion of the muscle that inserts on a rib) and subslip (superficial or deep subdivision of the slip after division along a loose areolar plane). All 260 slips could be separated into a deep and a superficial subslip, yielding a total of 520 subslips. A branch of the serratus artery (a terminal branch of the thoracodorsal artery serving the lower five to seven slips of the muscle) and a branch of the long thoracic nerve were identified for each of these. Deep subslips were thinner than superficial subslips, both at the origin of the slip on the rib periosteum (2.4 mm versus 3.0 mm, p < 0.0001) and centrally at the serratus artery (3.3 mm versus 4.0 mm, p < 0.0001). In addition, the subslips of the most inferior slip were thinner than those of more superior slips, both at the origin of the slip (2.3 mm versus 2.8 mm, p < 0.0001) and at the serratus artery (3.0 mm versus 3.8 mm, p < 0.0001). Fine anastomosing vessels were present between the slips and the subslips. The average number of anastomosing vessels present between adjacent slips was 1.7, and 2.1 anastomosing vessels were present between the subslips of a given slip. Given the thinness of these vessels (all less than 0.2 mm) compared with those of the vascular pedicle of the subslip (mean, 0.7 mm; all greater than 0.4 mm), the authors believe these can be safely divided without compromising subslip vascularity. After division of these vessels, a mean length of 9.6 +/- 1.5 cm is available to allow independent orientation of each subslip. When the serratus muscle flap is separated into its component subslips, a maximum of 10 possible force vectors may be transferred on a single vascular pedicle. Subslips are significantly thinner than donor muscles commonly used today. These two advantages offer the potential for significant functional and aesthetic improvement when the serratus anterior muscle flap is used for face and hand reanimation. Mimetic muscles such as the orbicularis oculi and orbicularis oris could possibly be reconstructed in their proper anatomical positions.     

Syntheses of acetylated steroid glycosides and selective cleavage of O-acetyl groups in sugar moiety

Acetylated 3β-O-β-glycosyl steroid derivatives were synthesized by the reaction of a new polyhydroxysteroid 3β,5α,6β-trihydroxypregn-16-en-20-one (2) with the peracetylated 1-bromo derivatives of d-glucose and d-galactose, respectively. Subsequent protection by excess acetic anhydride in pyridine selectively gave the 6β-O-acetylated steroid glycosides. Deprotection of the acetylated steroid glycosides separately with moderate catalysis dibutyltin oxide in methanol selectively removed all acetyl groups of sugar moiety, whereas the acetyl group of the steroid part was retained. The structures of the steroid glycosides were confirmed by mass spectrometry, NMR and IR. The complete protocol was shown to be non-destructive at all stages to the sugar moieties and the steroid nucleus. These regioselective reactions open a route to the synthesis of a series of closely related isomers of 2 and other widespread polyhydroxysteroids and steroid glycosides in marine organisms and some terrestrial species.     

Chloroplast DNA inheritance and variation in <Emphasis Type="Italic">Leucadendron</Emphasis> species (Proteaceae) as revealed by PCR-RFLP

The inheritance of chloroplast DNA (cpDNA) in Leucadendron species was studied by polymerase chain reaction–restriction fragment length polymorphism (PCR–RFLP) analysis. A total of 100 progeny from five interspecific crosses involving seven parental species were tested, and all progeny exhibited the cpDNA restriction fragment pattern of the female parent, indicating that cpDNA in Leucadendron is maternally inherited. PCR-RFLP was also employed to study cpDNA variation among 21 Leucadendron species. Parsimony analysis using a heuristic search resulted in a phylogenetic tree that showed limited agreement to the taxonomic classification of Leucadendron species, based on morphological characteristics. The incongruence between cpDNA phylogenetic and taxonomic groupings in Leucadendron may be due to reticulate evolution involving a combination of hybridization and introgression, convergent evolution and/or lineage sorting at the interspecific, intersubsectional and intersectional levels.     

Identification and molecular characterization of a novel y-type Glu-Dt 1 glutenin gene of Aegilops tauschii

A novel y-type high-molecular-weight glutenin subunit possessing a slightly faster mobility than that of subunit 1Dy12 in SDS-PAGE, designated 1Dy12.1^t in Aegilops tauschi, was identified by one- and two-dimensional gel and capillary electrophoresis. Its coding gene at the Glu-D ^t 1 locus was amplified with allele-specific-PCR primers, and the amplified products were cloned and sequenced. The complete nucleotide sequence of 2,807 bp containing an open reading frame of 1,950 bp and 857 bp of upstream sequence was obtained. A perfectly conserved enhancer sequence and the –300 element were present at positions of 209–246 bp and 424–447 bp upstream of the ATG start codon, respectively. The deduced mature protein of 1 Dy12.1^t subunit comprised 648 amino acid residues and had a Mr of 67,518 Da, which is slightly smaller than the 1Dy12 (68,695 Da) but larger than the 1Dy10 (67,495 Da) subunits of bread wheat, respectively, and corresponds well with their relative mobilities when separated by acid-PAGE. The deduced amino acid sequence indicated that the 1Dy12.1^t subunit displayed a greater similarity to the 1Dy10 subunit, with only seven amino acid substitutions, suggesting that this novel gene could have positive effect on bread-making quality. A phenetic tree produced by nucleotide sequences showed that the x- and y-type subunit genes were respectively clustered together and that the Glu-D ^t 1y12.1 gene of Ae. tauschii is closely related to other y-type subunit genes from the B and D genomes of hexaploid bread wheat.Communicated by H.F. Linskens     

Binding of an aminoacridine derivative to a GAAA RNA tetraloop

RNA tetraloops are common secondary structural motifs in many RNAs, especially ribosomal RNAs. There are few studies of small molecule recognition of RNA tetraloops although tetraloops are known to interact with RNA receptors and proteins, and to form nucleation sites for RNA folding. In this paper, we investigate the binding of neomycin, kanamycin, 2,4-diaminoquinazoline, quinacrine, and an aminoacridine derivative (AD1) to a GAAA tetraloop using fluorescence spectroscopy. We have found that AD1 and quinacrine bind to the GAAA tetraloop with the highest affinity of the molecules examined. The equilibrium dissociation constant of the AD1-GAAA tetraloop complex was determined to be 1.6 microM. RNase I and lead acetate footprinting experiments suggested that AD1 binds to the junction between the loop and stem of the GAAA tetraloop.     

Design and synthesis of conformationally constrained 3-(N-alkylamino)propylphosphonic acids as potent agonists of sphingosine-1-phosphate (S1P) receptors

A series of conformationally constrained 3-(N-alkylamino)propylphosphonic acids were systematically synthesized and their activities as S1P receptor agonists were evaluated. Several pyrrolidine and cyclohexane analogs had S1P receptor profiles comparable to the acyclic lead compound, 3-(N-tetradecylamino)propylphosphonic acid (3), lowered circulating lymphocytes in mice after iv administration and were thus identified as being suitable for further investigations.     

(2-amino-phenyl)-amides of omega-substituted alkanoic acids as new histone deacetylase inhibitors

A variety of omega-substituted alkanoic acid (2-amino-phenyl)-amides were designed and synthesized. These compounds were shown to inhibit recombinant human histone deacetylases (HDACs) with IC(50) values in the low micromolar range and induce hyperacetylation of histones in whole cells. They induced expression of p21WAF1/Cip1 and caused cell-cycle arrest in human cancer cells. Compounds in this class showed efficacy in human tumor xenograft models.