Identification and estimation of the proportion of limiting cell types involved in the phytohemagglutinin response by limiting cell dose-response analysis

Fluoresceinated peanut agglutinin (PNA-FITC) and a monoclonal anti-T-cell antibodies were used to identify human thymocyte subpopulations. The phenotypes of PNA+ and PNA? thymocytes were studied using two different techniques: agglutination with PNA and double-labeling immunofluorescence. The mitogen-responsive PNA- subset was shown to include early thymocytes bearing the OKT9 antigen as well as lymphocytes with the OKT3 phenotype. Nearly all PNA+ thymocytes were found to bind simultaneously OKT4, OKT6, and OKT8 antibodies, whereas about 30% of them weakly bind the OKT3 antibody. These data suggest the existence of several intermediate stages of intrathymic differentiation, including a subset simultaneously bearing the OKT6- and OKT3-defined antigens.     

辽东山区长白落叶松人工林天然更新障碍分析

通过对辽东山区不同间伐强度下长白落叶松林内种子库,种子萌发,幼苗出现、成活与生长的观测,分析了长白落叶松天然更新的主要影响因素.结果表明:40年生落叶松人工林的种子雨中,有30%的种子有活力,可以满足天然更新的需要;土壤种子库的种子主要分布在枯枝落叶层,4月下旬林内种子开始萌发,6月幼苗数量达到最大,幼苗累计出现率与间伐强度(光照)之间无显著相关,只受到地被物的影响;随间伐强度的增加,幼苗平均存活率提高,但林下幼苗生长缓慢,苗高均不超过6 cm;林内当年幼苗9月全部消失,没有超过1年生的幼苗,但皆伐迹地的更新幼苗存活较多、生长良好.初步确定地被物和光照是辽东山区长白落叶松天然更新的主要障碍因子.     

Lewis (Le) blood group system phenotypes and genotypes

The Lewis blood group system in humans, designated with number 007 and symbol Le, consist of two different fucose containing carbohydrate antigen structures abbreviated Le^a+ (LE-1) and Le^b+ (LE-2). The expression of these two carbohydrate sequences are phenotype determinants. The Le^a+ antigen sequence is triasaccharide β-D-Galp-(1- 3)-[α-L-Fucp-(1-4)]-D-GlcpNAc. The Le^b+ antigen sequence is tetrasaccharide α-L-Fucp-(1-2)-β-D-Galp-(1-3)- [α-L-Fucp-(1-4)]-D-GlcNpAc. Biosynthesis of Le blood group glycan antigens is catalyzed by fucosyltransferase 2 (FUT2) and fucosyltransferase 3 (FUT3) enzymes. These enzymes are encoded by two dominant autosomal genes named FUT2, also referred as secretory (Se) gene, and FUT3, both having multiple alleles. These two genes determine Lewis blood group genotypes. Sequencing of fucosyltransferase genes, RNAs and fucosyltransferase enzymes and the determination of their structures, together with functional studies including spatial and temporal expression patterns, showed preservation of the catalytic domain within prokaryotes and eukaryotes, with a high level of diversity in structural and functional properties. Six different Le blood group phenotypes exist, taking in account that Le and ABO blood group antigens both comprise terminal sequences on the same branched glycan molecules: Le^a+b-, Le^a-b+, Le^a-b-, Le^a+b+, ALe^a-b+, and BLe^a-b+. Le antigens are part of glycan structures synthetized in glycolipids or glycoprotein form in the endoderm and not in the erythrocyte precursor cell. They are present on the cell surface of blood cells, in plasma and in secretory fluids. Le glycolipids are adsorbed from plasma on the cell surface of erythrocytes, platelets, lymphocytes and endothelial cells.     

An analysis of network reciprocity in Prisoner's Dilemma games using Full Factorial Designs of Experiment

Despite hundreds of studies on the Prisoner's Dilemma (PD) game, understanding about network reciprocity remains a unsolved puzzle. Thus, we performed a series of Full Factorial Design of Experiments (FFDOE) to evaluate what dominates emerging cooperation in the PD game on various networks. The results qualitatively reveal the influence of each factor and show that some combinations of factors have complicated interactions. Remarkably, the choice of strategy update rule or update dynamics is much more important than the type of network imposed or, at least, the factorial effect of the average degree of the network reported by Nowak (Science 314, 5805, 1560-1563, 2006) and Ohtsuki et al. (Nature 441, 502-505, 2006). Furthermore, the decision of which PD game type to investigate (whether all PD games, PD-Chicken boundary games or Donor & Recipient games) is important for discussing network reciprocity.     

Lipopolysaccharide structures of Helicobacter pylori wild-type strain 26695 and 26695 HP0826::Kan mutant devoid of the O-chain polysaccharide component

We describe a re-investigation of the structure of the lipopolysaccharide (LPS) from Helicobacter pylori genomic strain 26695 and its corresponding HP0826::Kan mutant lacking the O-chain component based on the in-depth NMR analysis of the oligosaccharide products obtained through the use of various degradation procedures performed on the purified LPS from both strains, as well as CE–MS data. New structural evidence indicates the presence of the linear arrangement of glucan and heptan portions of the LPS attached through -6-α-ddHep-3-α-l-Fuc-3-β-GlcNAc- fragment to the inner core dd-heptose residue. This structure differs from previously reported structures of the H. pylori 26695 LPS in several aspects.     

Resource utilization by deep-sea sharks at the Le Danois Bank, Cantabrian Sea, north-east Atlantic Ocean

The feeding habits of birdbeak dogfish Deania calcea, velvet belly lantern shark Etmopterus spinax and blackmouth catshark Galeus melastomus at Le Danois Bank, Cantabrian Sea, south Bay of Biscay were studied in relation to their bathymetric distribution. Deep‐sea sharks were collected during two multidisciplinary surveys carried out in October 2003 and April 2004 at the Le Danois Bank. Two different habitats were defined: (1) the top of the bank, ranging from 454 to 642 m depth and covered by fine‐sand sediments with a low percentage of organic matter, and (2) the inner basin located between the bank and the Cantabrian Sea's continental shelf, at depths of 810–1048 m, which was characterized by a high proportion of silt and organic matter. Deania calcea was not present at the top of the bank but was abundant below 642 m, while E. spinax was abundant in the shallower top of the bank but was not found in the deeper inner basin. There was almost no bathymetric overlap between these two deep‐sea shark species. Galeus melastomus was found over the whole depth range. There seemed to be an ontogenetic segregation with depth for this species, however, since 80% of the specimens collected at the top of the bank were < 600 mm total length (L_T) (mean 510 mm L_T), whereas larger individuals (mean 620 mm L_T) inhabited deeper zones. Galeus melastomus exhibited a significantly higher feeding intensity than both E. spinax at the top of the bank and D. calcea in the inner basin. Little dietary overlap between D. calcea and G. melastomus in the inner basin was found, with D. calcea being an ichthyophagous predator while the diet of G. melastomus at these depths was composed of a variety of meso‐bathypelagic shrimps (e.g. Acantephyra pelagica, Pasiphaea spp. and Sergia robusta), cephalopods and fishes. The diets of E. spinax and G. melastomus at the top of the bank showed a high dietary overlap of euphausiids, which represented the main prey taxa for both species. Euphausiids declined in abundance with depth which was reflected in the diet of G. melastomus. The cluster analysis of prey affinities among hauls depicted two major groups, corresponding to the two different habitats (top of the bank and inner basin). Redundancy analysis also indicated top–basin segregation, with euphausiids representing the main prey taxa at the top of the bank and bathypelagic shrimps in the inner basin. Euphausiids and Micromesistius poutassou were key prey within the Le Danois Bank ecosystem since they were positively selected by the three deep‐sea shark species. These results show that the feeding ecology of these predators in Le Danois Bank ecosystem is highly influenced by depth‐related variables, as a result of changes in prey availability. Overall results were analysed in relation to the deep‐sea Le Danois ecosystem structure and functioning.     

Le Fort I型截骨术定位平面的应用解剖学研究

目的：研究Le Fort I型截骨术与上颌牙根尖的关系,为临床合理制订截骨平面提供解剖学依据。方法：选择上颌牙槽清晰或出土后仍有牙保留的颅骨,在颅骨梨状孔下缘至上颌结节作一连线作为模拟Le Fort I型术式截骨水平,以上颌牙槽缘为标志,用游标卡尺测量每侧上颌各牙的牙槽缘至上述模拟截骨水平的距离及牙槽缘至各牙根尖端的长度,然后计算出上颌各牙根尖至Le Fort I型术式截骨线的距离。结果：上颌各牙相对的牙槽缘至Le FortI型术式截骨线的距离,从中切牙至第二磨牙逐渐缩小,右侧中切牙为21．09±1．53mm,左侧中切牙为20．96±1．64mm,右侧第二磨牙为14．94±1．52mm,左侧第二磨牙为14．95±1．59mm;上颌各牙根尖至Le Fort I型术式截骨水平的距离,从中切牙至第二磨牙也逐渐缩小,而两侧尖牙牙根尖距离Le Fort I型术式截骨线的距离右侧为4．49±1．74mm,左侧为4．69±2．14mm,第二磨牙牙根尖距离Le Fort I型术式截骨线的距离右侧为4．65±1．63mm,左侧为4．49±1．89,两侧尖牙牙根尖和第二磨牙牙根尖至Le Fort I型术式截骨水平的距离均比较接近。结论：上颌各牙根尖至LeFortI型术式截骨线的距离均在4mm以上,根据前牙中尖牙牙根尖的位置和后牙中第二磨牙牙根尖的位置,Le Fort I型术式截骨线水平在13、23（3｜3）根尖及27、27（7｜7）根尖上方4mm以上,按此平面作截骨水平较为安全,不易损伤牙根。     

四川鱼类寄生吸虫Ⅱ.尾孔科、孔肠科和鳞肉科一新属四新种(吸虫纲:复殖目)

本文描述了采自四川鱼类肠道的复殖吸虫一新属四新种,它们是:1.(鱼兆)尾孔吸虫,新种Urotrema glyptothoraci sp.nov.,2.裂腹鱼斜孔吸虫,新种Plagioporus(Plagioporus)schizothoraci sp.nov.,3.异巢斜孔吸虫,新种Plagioporus(Plagioporus)allovaris sp.nov.,4.类宫殖属,新属Hysterogonoidet gen.nov.及模式种——双囊类宫殖吸虫,新种Hysterogonoldes disaccus sp.nov.。这些新属新种分别隶于尾孔科Urotrematidae、孔肠科Opecoelidae和鳞肉科Lepocreadiidae。