Morphophysiological dormancy in seeds of the ANA grade angiosperm Schisandra arisanensis (Schisandraceae)

We determined the kind of seed dormancy in Schisandra arisanensis, an ANA grade ([A]mborellales [N]ymphaeales [A]ustrobaileyales) angiosperm with medicinal value. Seeds have small underdeveloped embryos, and following seed maturity their length increased approximately 360% before radicle emergence. Germination was delayed 6–8 weeks, and the percentage and rate were much higher at 15/6, 20/10 and 25/15°C than at 30/20°C. For seeds incubated at 5/5°C (8 weeks) → 15/6°C (4 weeks) → 20/10°C (8 weeks) → 25/15°C (12 weeks) → 20/10°C (5 weeks), embryos grew at 15/6°C → 20/10°C, and almost all seeds that germinated (89%) did so at 20/10°C → 25/15°C. When seeds were incubated in a complementary temperature sequence, 25/15°C (12 weeks) → 20/10°C (8 weeks) → 15/6°C (4 weeks) → 5/5°C (9 weeks) → 15/6°C (4 weeks), embryos grew at 25/15°C → 20/10°C. Nearly all seeds that germinated (93%) did so at 25/15°C → 20/10°C and at 15/6°C following 9 weeks at 5/5°C. Based on the temperature requirements for embryo growth and seed germination, seeds of this species have non‐deep simple morphophysiological dormancy (C_1bB).     

CpG联合铝佐剂对HCV免疫原体液免疫作用的影响

目的:探讨胞苷酸鸟苷寡脱氧核苷酸(CpG ODN)联合铝佐剂对丙型肝炎病毒(HCV)重组免疫原的体液免疫作用。方法:采用高交叉HCV-HVR1和E1重组蛋白与CpG ODN、铝佐剂组合,免疫BALB/c小鼠后以ELISA、酶联免疫斑点测定、流式细胞术、免疫沉淀等方法检测相关体液免疫指标和免疫血清多抗的交叉反应性。结果:CpG联合铝佐剂激发了最高的特异性抗体滴度;佐剂通过提高抗体分泌细胞数量、增加脾脏中记忆B细胞数量、增加脾淋巴细胞IL-6、IL-10分泌浓度实现体液免疫增效;CpG则能提高免疫效率,联合铝佐剂时显著提高浆细胞数量;12份HCV阳性血清中有10份可与多抗HVR1 IgG发生免疫沉淀。结论:CpG和铝佐剂联合应用具有协同作用,多抗HVR1 IgG具有较好的交叉反应性。     

两个苜蓿品种营养器官解剖结构特征比较

为了明确具有极强抗虫特性的‘草原4号紫花苜蓿’(Medicago sativa L.‘Caoyuan No.4’) 营养器官的解剖特征,该研究选择具有抗蓟马特性较强的‘草原2号杂花苜蓿’(Medicago varia Martin.‘Caoyuan No.2’)为对照,采用显微镜观察比较两品种的根、茎、叶解剖结构特征,为揭示‘草原4号紫花苜蓿’ 抗蓟马特性提供理论依据。结果显示：(1)‘草原4号紫花苜蓿’根部解剖结构的皮层薄壁细胞厚度、内皮层厚度、形成层厚度、木质部厚度和木射线宽度等5个指标均极显著高于(P＜0.01)‘草原2号杂花苜蓿’,其中木射线宽度(159.37 μm)是‘草原2号杂花苜蓿’的1.82倍。(2)‘草原4号紫花苜蓿’的茎部厚角组织厚度(21.4 μm)极显著高于‘草原2号杂花苜蓿’(P＜0.01),而韧皮部宽度、髓直径却均极显著低于‘草原2号杂花苜蓿’(P＜0.01)。(3)‘草原4号紫花苜蓿’叶片解剖构造的7个指标均极显著高于‘草原2号杂花苜蓿’(P＜0.01),其中栅栏组织层数(2～3层)极明显地高于‘草原2号杂花苜蓿’(1~2层)。研究表明,‘草原4号紫花苜蓿’的组织结构特征具有明显的抗虫特征,且其组织的抗虫特征比‘草原2号杂花苜蓿’更为突出。     

HLA-DRB1 shared epitope genotyping using the revised classification and its association with circulating autoantibodies,acute phase reactants,cytokines and clinical indices of disease activity in a cohort of South African rheumatoid arthritis patients

Introduction  

The revised shared epitope (SE) concept in rheumatoid arthritis (RA) is based on the presence (S) or absence (X) of the SE RAA amino acid motif at positions 72 to 74 of the third hypervariable region of the various human leucocyte antigen (HLA)-DRB1 alleles. The purpose of this study was to investigate SE subtypes on the basis of the American College of Rheumatology 1987 revised criteria for the classification of RA in a cohort of South African RA patients (n = 143) and their association with clinical and circulating biomarkers of disease activity (autoantibodies, acute phase reactants and cytokines).     

Evolutionary dynamics of tandem repeats in the mitochondrial DNA control region of the minnow Cyprinella spiloptera

Length variation due to tandem repeats is now recognized as a common feature of animal mitochondrial DNA; however, the evolutionary dynamics of repeated sequences are not well understood. Using phylogenetic analysis, predictions of three models of repeat evolution were tested for arrays of 260-bp repeats in the cyprinid fish Cyprinella spiloptera. Variation at different nucleotide positions in individual repeats supported different models of repeat evolution. One set of characters included several nucleotide variants found in all copies from a limited number of individuals, while the other set included an 8- bp deletion found in a limited number of copies in all individuals. The deletion and an associated nucleotide change appear to be the result of a deterministic, rather than stochastic, mutation process. Parallel origins of repeat arrays in different mitochondrial lineages, possibly coupled with a homogenization mechanism, best explain the distribution of nucleotide variation.      

Substructural specificity and polyvalent carbohydrate recognition by the Entamoeba histolytica and rat hepatic N- acetylgalactosamine/galactose lectins

Both the Entamoeba histolytica lectin, a virulence factor for the causative agent of amebiasis, and the mammalian hepatic lectin bind to N-acetylgalactosamine (GalNAc) and galactose (Gal) nonreducing termini on oligosaccharides, with preference for GalNAc. Polyvalent GalNAc- derivatized neoglycoproteins have >1000-fold enhanced binding affinity for both lectins (Adler,P., Wood,S.J., Lee,Y.C., Lee,R.T., Petri,W.A.,Jr. and Schnaar,R.L.,1995, J. Biol. Chem ., 270, 5164-5171). Substructural specificity studies revealed that the 3-OH and 4-OH groups of GalNAc were required for binding to both lectins, whereas only the E.histolytica lectin required the 6-OH group. Whereas GalNAc binds with 4-fold lower affinity to the E.histolytica lectin than to the mammalian hepatic lectin, galactosamine and N-benzoyl galactosamine bind with higher affinity to the E. histolytica lectin. Therefore, a synthetic scheme for converting polyamine carriers to poly-N-acyl galactosamine derivatives (linked through the galactosamine primary amino group) was developed to test whether such ligands would bind the E.histolytica lectin with high specificity and high affinity. Contrary to expectations, polyvalent derivatives including GalN6lys5, GalN4desmosine, GalN4StarburstTMdendrimer, and GalN8StarburstTMdendrimer demonstrated highly enhanced binding to the mammalian hepatic lectin but little or no enhancement of binding to the E.histolytica lectin. We propose that the mammalian hepatic lectin binds with greatest affinity to GalNAc "miniclusters," which mimic branched termini of N-linked oligosaccharides, whereas the E.histolytica lectin binds most effectively to "maxiclusters," which may mimic more widely spaced GalNAc residues on intestinal mucins.      

Revisiting the Phylogenetic Position of Synchroma grande

ABSTRACT. Two new classes Synchromophyceae and Picophagea, belonging to the heterokonts, have been proposed recently in separate studies of 18S rRNA phylogenies. Here we revise the 18S phylogeny of these classes by including all available sequenced species and applying Bayesian and maximum likelihood methods; Synchroma grande groups with the photophagotrophic Chlamydomyxa labyrinthuloides with high statistical support. This clade is sister to Chrysophyceae, together they share a common ancestry. Our results show that the creation of class Synchromophyceae by Horn et al. was premature, because they did not include data from the closely related C. labyrinthuloides and Picophagus flagellatus species. A revision of these classes should include additional species and most likely multigene phylogenies.     

High risk populations and HIV-1 infection in China

INTRODUCTION HIV has spread to all of China’s 31 provinces, autono- mous regions and municipalities, creating one of the fast- est-growing HIV/AIDS epidemics in the world [1,2]. The HIV/AIDS epidemic in China has gone through three phases: the Entry Phase (1985 -1988), the Spreading Phase (1989-1994) and the Expansion Phase (1995- present). The striking increase of HIV-1 infections over the past few years may herald entry into a new fourth phase that will include much larger nu…     

Antiplatelet and anticoagulant therapy in elective percutaneous coronary intervention

Thrombosis plays a major role in acute vessel closure both after coronary balloon angioplasty and after stenting. This review will address the role of antiplatelet and anticoagulant therapy in preventing early thrombotic complications after percutaneous coronary intervention. The focus will be on agents that are routinely available and commonly used.