植物源调节剂对水稻的影响

植物源调节剂是利用艾蒿为主要原料,首次用提取的混合物研制成的一种植物生长调节剂,使用80mg/L的植物源调节剂混合物水溶液,分别在水稻苗期、拔节期、孕穗期叶面喷洒,清水对照。结果表明:植物源调节剂使水稻增产11.38%,千粒重增加11.45%。株干重增加了17.1%。在灌浆期连续测定表明:相对于CK,穗粒重增加10.9%,叶绿素含量提高14.41%。品质分析结果为:可溶性糖含量提高15.57%、游离氨基酸含量提高18.52%、淀粉含量提高1.59%,可溶性蛋白质降低22.17%、粗纤维降低1.95%、粗脂肪降低1.22%。该植物源调节剂对水稻的生长和产量都有显著的促进效应。     

华中五味子抗氧化和细胞毒活性研究

我们研究了华中五味子的根、茎、叶、果实乙醇提取物对脂性自由基DPPH及超氧阴离子的清除作用,同时观察了四种不同提取物在体外对肿瘤细胞株的细胞毒作用。我们发现,华中五味子根的乙醇提取物清除自由基活性和对肿瘤细胞杀伤作用比茎、叶和果实的提取物都强,研究结果提示华中五味子的根可以作为抗氧化剂的新来源。     

雪莲PBP基因表达载体的构建

目的:利用新疆雪莲特殊功能基因磷脂酰乙醇胺结合蛋白基因(XLPBP)与基础质粒构建植物表达载体pXLPBP,为介导该基因在植物中表达,以期提高植物抗寒力的转基因研究打下基础。方法:利用设计好的两端加有EcoRⅠ酶切位点的引物,对XLPBP全长基因片段进行PCR扩增,获得700bp左右大小的片段,将其纯化回收并与同样经过EcoRⅠ酶切的质粒pCAMBIA3301连接;然后采用冻融法和电击法,将含XLPBP基因的载体pCAMBIA3301转入根癌农杆菌中。结果:通过一系列分子克隆方法获得含雪莲XLPBP基因的植物表达载体,并经PCR实验证实。结论:利用以自身携带的非编码区为调控序列的XLPBP全长基因和双向表达载体pCAMBIA3301为基础构建植物表达载体,可望提高外源基因表达量。     

竹亚科刚竹属植物新资料

描述了竹亚科Bambusoideae刚竹属Phyllostachys Sieb. et Zucc.的2个新种和5个新变型：瓜竹Ph. longiciliata、浙江甜竹Ph. zhejiangensis、黄槽黄古竹Ph. angusta f. flavosulcata、绿槽人面竹Ph. aurea f. koi、蝶毛竹 Ph. edulis f. abbreviata、黄条燥壳竹Ph. hirtivagina f. flavovittata和花竹Ph. nidularia f. basipilis;作出3个新组合变型：厚皮毛竹Ph. edulis f. pachyloen、安吉锦毛竹Ph. edulis f. anjiensis和花秆早竹Ph. violascens f. viridisulcata;对金条竹Ph. aureosulcata f. flavostriata、对花竹Ph. bambusoides f. duihuazhu、黄槽斑竹Ph. bambusoides f. mixta和黄皮毛竹Ph. edulis f. holochrysa的模式标本给予了重新指定。     

Le Paléolithique ancien de l’Europe orientale et du Caucase

Currently, only Tréhougol’naya Cave has reliably dated evidence for human settlement in Eastern Europe and Caucasus, from the beginning through the middle of the Middle Pleistocene. In Eastern Europe, assemblages from Khriatchi and Mikhailovskoé, and possibly Darvagchai I, appear to be the only stratified locations that tentatively can be compared (despite problems with these materials) with Tréhougol’naya. In the eastern limits of Central Europe, layer VI in Korolevo I is the only stratified assemblage that may be compared with Tréhougol’naya. All these Lower Paleolithic occupations yielded the Pre-Mousterian small tool industries with some pebble tools, but without Acheulean bifaces and Levallois technique. These data suggest that Eastern Europe lies outside the distribution range of the Acheulean techno-complex demarcated with the “Movius Line”. In the Southern Caucasus, the Dmanissi hominine and lithic records document the fact that the earliest small-brained humans – probably later H. habilis-rudolfensis or earlier H. ergaster-erectus hominids bearing Pre-Oldowan technology – initially left Africa and appeared in Western Asia as early as 1.8 Ma ago. However, in the Southern Caucasus, the available chronological data indicate that the Acheulean complex has a later temporal appearance here compared to the Upper Acheulean or Acheulo-Yabrudian in Western Asia. Two main Upper Acheulean industrial variants currently can be recognized in the Southern Caucasus. The first, called the Kudarian by the author (from the caves of Kudaro I, Kudaro III, and Azyk), is characterized by lithics made from mostly siliceous rocks, rare Acheulean bifaces, and non-Levallois flaking technique. The second variant is characterized by lithics made from volcanic rocks, numerous Acheulean bifaces, and often more laminar or Levallois debitage. It can be suggested that there are independent origins for these Southern Caucasus Upper Acheulean industrial variants. Possible roots of the Acheulean assemblages of Kudarian variant might be in the local earlier Lower Paleolithic small tool assemblages with some pebble tools but without Acheulean bifaces. The other Caucasus variant of the Upper Acheulean appears to be related to the Levantine Upper Acheulean.     

Burn injury suppresses human dermal dendritic cell and Langerhans cell function

Human skin contains epidermal Langerhans cells (LCs) and dermal dendritic cells (DCs) that are key players in induction of adaptive immunity upon infection. After major burn injury, suppressed adaptive immunity has been observed in patients. Here we demonstrate that burn injury affects adaptive immunity by altering both epidermal LC and dermal DC functions. We developed a human ex vivo burn injury model to study the function of DCs in thermally injured skin. No differences were observed in the capacity of both LCs and dermal DCs to migrate out of burned skin compared to unburned skin. Similarly, expression levels of co-stimulatory molecules were unaltered. Notably, we observed a strong reduction of T cell activation induced by antigen presenting cell (APC) subsets that migrated from burned skin through soluble burn factors. Further analyses demonstrated that both epidermal LCs and dermal DCs have a decreased T cell stimulatory capacity after burn injury. Restoring the T cell stimulatory capacity of DC subsets might improve tissue regeneration in patients with burn wounds.     

High resolution positioning of intron ends on the nucleosomes

High resolution sequence-directed nucleosome mapping is applied to 36,000 sequences containing splice junctions, from five different species. As it has been also shown in previous studies, the junctions are found to be preferentially located within nucleosomes. Moreover, the orientation of guanine residues at the GT- and AG-ends of introns within the nucleosomes is such that the guanines are positioned nearest to the surface of histone octamers, 3 and 4 bases upstream from the local DNA pseudo-dyads passing through minor grooves oriented outwards. Since the guanine residues are the most vulnerable to spontaneous damage within the cell (primarily, depurination and oxidation) such positioning of the splice junctions minimizes the damage that is caused by free radicals and highly reactive metabolites.     

Water relations in culture media influence maturation of avocado somatic embryos

Application of transformation and other biotechnological tools in avocado (Persea americana Mill.) is hampered by difficulties in obtaining mature somatic embryos capable of germination at an acceptable rate. In this work, we evaluated the effect of different compounds affecting medium water relations on maturation of avocado somatic embryos. Culture media were characterized with respect to gel strength, water potential and osmotic potential. Improved production of mature somatic embryos was achieved with gelling agent concentrations higher than those considered standard. The osmotic agents such as sorbitol and PEG did not have positive effects on embryo maturation. The number of w-o mature somatic embryos per culture was positively correlated with medium gel strength. Gel strength was significantly affected by gelling agent type as well as by gelling agent and PEG concentration. Medium water potential was influenced by sorbitol concentration; incorporation of PEG to a culture medium did not affect medium water potential. The highest maturation results were achieved on a medium gelled with 10 g l⁻¹ agar. Moreover, these somatic embryos had improved germination rates. These results corroborate the role of water restriction as a key factor controlling maturation of somatic embryos.     

Evidence for the transmission of information through electric potentials in injured avocado trees

Electrical excitability and signaling, frequently associated with rapid responses to environmental stimuli, have been documented in both animals and higher plants. The presence of electrical potentials (EPs), such as action potentials (APs) and variation potentials (VPs), in plant cells suggests that plants make use of ion channels to transmit information over long distances. The reason why plants have developed pathways for electrical signal transmission is most probably the necessity to respond rapidly, for example, to environmental stress factors.We examined the nature and specific characteristics of the electrical response to wounding in the woody plant Persea americana (avocado). Under field conditions, wounds can be the result of insect activity, strong winds or handling injury during fruit harvest. Evidence for extracellular EP signaling in avocado trees after mechanical injury was expressed in the form of variation potentials. For tipping and pruning, signal velocities of 8.7 and 20.9 cm/s, respectively, were calculated, based on data measured with Ag/AgCl microelectrodes inserted at different positions of the trunk. EP signal intensity decreased with increasing distance between the tipping and pruning point and the electrode. Recovery time to pre-tipping or pre-pruning EP values was also affected by the distance and signal intensity from the tipping or pruning point to the specific electrode position. Real time detection of remote EP signaling can provide an efficient tool for the early detection of insect attacks, strong wind damage or handling injury during fruit harvest.Our results indicate that electrical signaling in avocado, resulting from microenvironment modifications, can be quantitatively related to the intensity and duration of the stimuli, as well as to the distance between the stimuli site and the location of EP detection. These results may be indicative of the existence of a specific kind of proto-nervous system in plants.     

Biostratigraphie,paléoécologie et zones d’acmé des foraminifères planctoniques au passage Crétacé-Paléogène dans la Téthys (Tunisie et Espagne) et l’Atlantique (France)

Biostratigraphical high-resolution analyses and quantitative data confirm that deposition is continuous across the K-Pg transition in several sections in Tunisia (El Kef, stratotype section) and Spain (Agost and Caravaca sections) located in the Tethyan realm and the Bidart sections in the Atlantic realm, without any relevant hiatus. The Upper Maastrichtian assemblages of planktic foraminifera from these sections are largely dominated by small biserial heterohelicids. They are associated to common species having planispiral test (i.e. globigerinelloids), trochospiral test (i.e. hedbergellids, rugoglobigerinids globotruncanids), to rare triserial heterohelicids (i.e. guembelitriids) and trochospiral species showing tubulospines (i.e. schackoinids). Stratigraphical ranges of these diverse taxa through the late Maastrichtian in the Tethyan and Atlantic realms show very few changes in the planktonic foraminiferal assemblages and most of the species are present in the Abathomphalus mayaroensis biozone. By our high-resolution sampling and the intensive research for the A. mayaroensis index species in the uppermost Maastrichtian samples, we confirm that this species is omnipresent up to the top of the Maastrichtian. Therefore, A. mayaroensis is present in almost all samples which are late Maastrichtian in age, but this species became very scarce in the uppermost Maastrichtian samples. This scarceness could be due to a climate cooling. A sharp decrease in relative abundance of the deep dwellers species, like as Abathomphalus intermedius and A. mayaroensis as well as in other keeled globotruncanids is observed at the studied sections from the Tethyan realm (indicative of low latitude) across the latest Maastrichtian. At the K/Pg boundary, all the globotruncanids disappeared. They are considered specialists living in tropical-subtropical deep seawater habitat. At this boundary, large and ornate heterohelicids also disappeared. Therefore, all the studied sections show that about 90 % of the Maastrichtian species became extinct according to a catastrophic mass extinction pattern. Only about 10 % crossed the K/Pg boundary and survived during the earliest Danian. The minor difference in the number of disappeared taxa is related to their latitude location or environment paleodepth. The changes in the species relative abundance, observed in the successive planktic foraminiferal assemblages, make it possible to recognize the Acme-stage 0 typical of the upper Maastrichtian interval. It is characterized by the highest species richness of Globotruncanids and heterohelicids specialists of tropical to subtropical marine conditions, the Acme-stage 1 typical of the Guembelitria cretacea Zone, and in particular of the Hedbergella holmdelensis Subzone dominated by “opportunists” species belonging to Guembelitria, the Acme-stage 2 which corresponds to the Pv. eugubina Zone dominated mainly by specimens belonging to Palaeoglobigerina and Parvularugoglobigerina and the Acme-stage 3 which characterizes mainly the Ps. pseudobulloides Zone dominated by biserial species belonging to Chiloguembelina and Woodringina.