Comparative morphology of the foliage leaf epidermis, with emphasis on papillae characters, in key taxa of woody bamboos of the Asian tropics (Poaceae: Bambusoideae)

The foliage leaf epidermis of 35 species representing 12 key genera of woody bamboos of the Asian tropics was investigated using light and scanning electron microscopy. The results indicated that papillae forms and distributional patterns around the stomatal apparatus of the abaxial foliage leaf epidermis were usually constant and were of great taxonomic significance at the specific and generic levels. However, papillae characters were not suitable for dividing subtribes within woody bamboos of the Asian tropics. On the basis of papillae characters, Schizostachyum s.s. and Cephalostachyum were confirmed, but their delimitations should be modified. The transfer of Leptocanna chinensis and Schizostachyum sanguineum into Cephalostachyum was supported, and Cephalostachyum virgatum and C .  pergracile were confirmed to be members of Schizostachyum s.s. The subtribe Racemobambosinae did not obtain support and Racemobambos appeared to be better placed in subtribe Bambusinae. Neomicrocalamus was supported as a close relative and better treated as a synonym of Racemobambos . Gigantochloa was closely related to Dendrocalamus .  © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society , 2008, 156 , 411–423.     

Interaction of some polyhexamethylene biguanides and membrane phospholipids in Escherichia coli

The interaction between some polyhexamethylene biguanides and the cell envelope of Escherichia coli has been investigated. An amine-ended dimer, (AED, n = 2), a polydisperse mixture (ICI plc) available as the active ingredient of Vantocil IB, (PHMB, n = 5.5), and a high molecular weight fraction, (HMW, n = greater than or equal to 10) of PHMB were used. The sensitivity of batch cultures depleted of magnesium (M-dep), phosphorus (P-dep) or glycerol (C-dep) towards the biocides was assessed by monitoring the rate and extent of potassium ion leakage. P-dep suspensions were particularly resistant to all these agents and possessed less than half the quantity of phospholipid of other cell types. This was compensated for by a proportionate increase in fatty acid and neutral lipid content of the cells. The reduction in phospholipid content was accounted for by decreases in phosphatidylglycerol (PG) and phosphatidylethanolamine (PE). Diphosphatidylglycerol (DPG) and phosphatidylserine (PS) content of the cultures remained unaffected by the depleting nutrient. Fourier-transform n.m.r. spectroscopy was used to study proton nuclei during the interaction of HMW, AED and PHMB with various phospholipid-vesicle preparations. The results strongly suggest that the biocides acted preferentially on the acidic phospholipids PG and DPG, rather than towards PE or PS. Resistance of P-dep cultures therefore reflected reductions in PG content. A molecular basis for the interaction of these compounds and membranes is proposed.     

Cloning and expression of the Erwinia chrysanthemi asparaginase gene in Escherichia coli and Erwinia carotovora

A genomic library of Erwinia chrysanthemi DNA was constructed in bacteriophage lambda 1059 and recombinants expressing Er. chrysanthemi asparaginase detected using purified anti-asparaginase IgG. The gene was subcloned on a 4.7 kb EcoRI DNA restriction fragment into pUC9 to generate the recombinant plasmid pASN30. The position and orientation of the asparaginase structural gene was determined by subcloning. The enzyme was produced at high levels in Escherichia coli (5% of soluble protein) and was shown to be exported to the periplasmic space. Purified asparaginase from E. coli cells carrying pASN30 was indistinguishable from the Erwinia enzyme on the basis of specific activity [660-700 units (mg protein)-1], pI value (8.5), and subunit molecular weight (32 X 10(3]. Expression of the cloned gene was subject to glucose repression in E. coli but was not significantly repressed by glycerol. Recombinant plasmids, containing the asparaginase gene, when introduced into Erwinia carotovora, caused increased synthesis of the enzyme (2-4 fold higher than the current production strain).     

内蒙古部分地区骆驼和羊寄生蜱虫病毒组学分析

为了解内蒙古地区蜱虫病毒组学的本底数据,采用病毒宏基因组学方法对在内蒙古阿拉善盟左旗、右旗和四子王旗地区3个采样点采集骆驼和羊体表寄生的1789只蜱虫样品进行病毒宏基因组学分析,并对特定病毒进行巢式PCR扩增和测序,通过Clustal W和MEGA7.0等生物信息学软件对获得的病毒基因序列进行遗传进化分析.数据显示,蜱虫样品携带包括植物、脊椎动物和非脊椎动物等来源的17个病毒科和一些未分类的病毒;其中,2株弹状病毒具有丰富的遗传多样性,与新疆地区和长江地区的弹状病毒的同源性达到98.5％和96.26％,提示蜱虫弹状病毒可能是通过羊和骆驼等动物贸易导致了新疆和内蒙古地区,以及内地的跨区域传播;细小病毒仅在羊来源的蜱虫中检测到,与中国河北地区的山羊血清中的细小病毒形成同一进化分支,我们推测蜱虫细小病毒在国内不同地区间可跨区域传播,在进化分析过程中,发现这种病毒与多种的细小病毒的同源性都不低于50％,提示细小病毒可能具有遗传稳定性;Tamdy病毒与来自阿塞拜疆、乌兹别克斯坦和美国的Tamdy病毒均具有极高的同源性,结果显示该病毒在内蒙古地区已经出现,并存在潜在流行的可能,有必要对Tamdy病毒进行进一步的监测;在本研究中,我们鉴定的白蛉病毒与来自新疆的亚洲璃眼蜱所携带的博乐蜱虱病毒形成同一个进化分支,与新型布尼亚病毒和Heartland virus病毒的同源性达到50％以上,该结果提示,我们发现的蜱虫白蛉病毒可能具有潜在的致病性,需要对其流行情况和致病性进行监测和研究.本研究为完善内蒙古部分地区蜱虫病毒的多样性和本底情况提供了重要的基础数据.     

Fibrinogen and fibrin in strong magnetic fields. Complementary results and discussion

When fibrin polymerizes in a strong magnetic field, it can be highly oriented. The structural diffraction study of the oriented polymer becomes thus possible. The magnetic birefringence can also be used to study the development of the polymer Fibrinogen in solution is weakly oriented in high magnetic fields. In this work we present complementary results and discussion. The validity of the comparison of the orientation parameters of fibrinogen and fibrin with those of other orientable known biological structures is discussed. The orientation of fibrin formed from fibrin monomer solution is compared to that of fibrin formed by the action of thrombin on fibrinogen. The conditions to obtain highly oriented fibrin gels suitable for three dimensional structure studies are also briefly discussed.     

多种天敌控制多种害虫的模糊数学模型

从生态经济学的原理出发，利用模糊集理论，探讨如何评价天敌控制多种害虫的为害作用，提出了多种天敌控制多种害虫的模糊数学模型。同时又得到了天敌对害虫的控制能力C，影响率G，影响强度H，及权数ω(x)的计算公式，以及在天敌作用下安全度的讨论与分析。     

Identification of up-regulated genes in human uterine leiomyoma by suppression subtractive hybridization

In searching for differentially expressed genes in human uterine leiomyomas (ULs), suppression sub-tractive hybridization was used to construct an UL up-regulated library, which turned out to represent 88genes. After two rounds of screening by reverse Northern analysis, twenty genes were proved to be up-regulated, including seventeen known genes and three genes with unknown function. All these genes werefirstly associated with UL. Three genes with notable difference were selected for Northern confirmationOur results proved the authenticity of the twenty genes. One gene named Phospholipase A2 (PLA2) showedup-regulation in 4/6 of the patients and investigation of tissue distribution indicated that it had obviousexpression in prostate, testis, liver, heart and skeletal muscle.