Slippery surfaces of carnivorous plants: composition of epicuticular wax crystals in<Emphasis Type="Italic"> Nepenthes alata</Emphasis> Blanco pitchers

Plants in the genus Nepenthes obtain a substantial nutrient supply by trapping insects in highly modified leaves. A broad zone of the inner surface of these pitchers is densely covered with wax crystals on which most insects lose their footing. This slippery wax surface, capturing prey and preventing its escape from the trap, plays a pivotal role in the carnivorous syndrome. To understand the mechanism of slipperiness, the present investigation aimed at an ultrastructural and physico-chemical characterization of the wax crystals in pitchers of N. alata Blanco. Scanning electron microscopy revealed that entire platelets protruded perpendicularly from the surface. Methods were developed that allowed the mechanical removal of wax crystals from the pitcher surface. It could be shown that the sampling was selective for the epicuticular wax, relevant for plant–insect interactions. The crystals consisted of a mixture of aliphatic compounds dominated by very-long-chain aldehydes. Triacontanal, at 43% the most abundant constituent, was largely responsible for crystal formation. Solubility data indicate that the Nepenthes crystals contained polymeric forms of this aldehyde. The resulting mechanical properties of the polymer crystals and the mechanism of slipperiness are discussed.Abbreviation SEM scanning electron microscopy     

Successful development of viable blastocysts from enhanced green fluorescent protein transgene-microinjected mouse embryos: comparison of culture media

To improve efficiency of transgenesis, we compared M16 and CZB embryo culture media, supporting development to blastocysts of FVB/N mouse pronuclear-eggs, microinjected with enhanced green fluorescent protein (EGFP) transgene. When EGFP-injected-eggs were cultured (120 hr), blastocyst development was significantly (P < 0.03) higher in M16 medium (72.5 +/- 2.4%) than that in CZB (13.2 +/- 4.3%) or CZBG (CZB with 5.6 mM glucose at 48 hr culture) (62.1 +/- 3.7%) media. Blastocyst development of noninjected embryos was higher in M16 (92.0 +/- 2.6%) and CZBG (83.9 +/- 3.9%) media than in CZB (31.9 +/- 2.8%) medium (P < 0.0001). However, percentages of morulae at 72 hr were comparable in all treatments. Developed blastocysts were better in M16 than in CZB or CZBG media. Consistent with this, mean cell number per blastocyst, developed from injected embryos, was significantly (P < 0.002) higher in M16 medium (79.6), than those in CZB (31.3) or CZBG media (60.7); similar with noninjected embryos. Cell allocation to trophectoderm (TE) and inner cell mass (ICM), i.e., TE:ICM ratio, for injected blastocysts in M16 (3.0) was less than (P < 0.05) those in CZB (4.2) and CZBG (4.4) media; similar with noninjected blastocysts. Moreover, blastocysts, developed in M16 and CZBG media, hatched, attached, and exhibited trophoblast outgrowth; 18% of them showed EGFP-expression. Importantly, blastocysts from M16 medium produced live transgenic "green" pups (11%) following embryo transfer. Taken together, our results indicate that supplementation of glucose, at 48 hr of culture (CZBG), is required for morula to blastocyst transition; M16 medium, containing glucose from the beginning of culture, is superior to CZB or CZBG for supporting development of biologically viable blastocysts from EGFP-transgene-injected mouse embryos.     

Morphology and development of the haptors among the Monocotylidae (Monogenea)

Monocotylid monogeneans inhabit a wide diversity of sites on their chondrichthyan hosts including the skin, gills, nasal fossae, urogenital system and coelom. The large variation in the morphology of the haptor appears to reflect this diversity in attachment sites. We demonstrate that the complexity of the haptor can be related to the habitat of the parasite. Generally, those parasites which live in habitats subject to strong water currents such as the gills and dorsal skin surface have more complex haptors than those in environments exposed to weaker or no water currents including the nasal fossae, urogenital system and body cavity. However, there can be considerable variation in haptoral components, even among congeners, living on the ‘gills’ of their hosts. The microhabitat was determined for Monocotyle helicophallus and M. spiremae, both from the gills of the pink whipray, Himantura fai, and M. corali from the gills of the cowtail ray, Pastinachus sephen. We demonstrate that differences in the morphology of the hamuli and the number and morphology of septal sclerites and marginal papillae among these species of Monocotyle can be related directly to their microhabitat. It also appears that different haptoral structures are important for attachment to the host at different stages in the development of the parasite, based on studies on the development and distribution of Neoheterocotyle rhinobatidis from the gills of the common shovelnose ray Rhinobatos typus. This revised version was published online in July 2006 with corrections to the Cover Date.     

Social status and growth rates as determinants of site attachment in juvenile Atlantic salmon

This paper describes an experimental study of the effects of food supply, growth rates and social interactions on homing by juvenile Atlantic salmon Salmo salar in response to displacement. Groups of five fish were housed in a section of an artificial stream and given either rations allowing maximum growth (the rich condition) or 0·1 of this amount (the poor condition); daily specific growth rates were significantly higher in the rich condition. After a 6-day settlement period, the fish were captured, displaced downstream and their movements recorded over the next 3 h. Prior to displacement, the fish showed a high degree of site fidelity and high levels of aggression. Dominant fish and those with stronger site attachment grew faster prior to displacement, these effects being independent. Following displacement, 24% of all fish returned to their previously favoured site and stayed there, 23% returned home initially, but subsequently moved on, 5% settled in a new site and 49% failed to move. The distribution of responses was identical for the rich and poor conditions, but fish that homed were dominant and had grown faster during the pre-displacement period.     

Attachment of Nontypable Haemophilus influenzae to Human Pharyngeal Epithelial Cells Mediated by a Ganglioside Receptor

Nontypable Haemophilus influenzae (NTHI) is one of the major pathogens of human respiratory infections and has the ability to attach to pharyngeal epithelial cells. We characterized the epithelial cell receptor to which NTHI bind. Neuraminidase pretreatment of pharyngeal epithelial cells resulted in a significant decrease in NTHI attachment, suggesting sialic acid as an important component of the receptor. The attachment was not decreased in NTHI pretreated with 1,000 μg/ml of fucose, N-acetyl-neuraminic acid, N-acetyl-glucosamine, N-acetyl-galactosamine, acetyl-salicylic acid and colominic acid. Only treatment with gangliosides D1a, D1b and D2 at a concentration of 12.5 μg/ml significantly decreased the attachment. On the other hand, treatment with gangliosides M1, M2, M3, D3, T1b and asialoganglioside M1 did not decrease the attachment of NTHI. Only ganglioside D2 inhibited the attachment significantly at a concentration of 12.5 ng/ml. Other isolates of NTHI showed a decrease in attachment after treatment with ganglioside D2. Treatment of cells with anti-human GD2 monoclonal antibody also decreased the attachment of NTHI in a dose-dependent manner. This study indicates that sialic acid glycoconjugate, GD2, is one of the receptors of NTHI on human pharyngeal epithelial cells.     

Experimental and computational studies of enantioseparation of structurally similar chiral compounds on amylose tris(3,5‐dimethylphenylcarbamate)

The enantioseparation of 14 structurally similar chiral solutes, with one or two chiral centers, are studied for a commercially important polysaccharide‐based chiral stationary phase, amylose tris(3,5‐dimethylphenylcarbamate) (ADMPC). Among these solutes, only two solutes show significant enantioresolutions of 2 to 2.5 in n‐hexane/2‐propanol (90/10, v/v) at 298 K. The retention factors of the chiral solutes vary significantly from 0.7 to 7.0, and they are compared with those of simpler nonchiral solutes having similar but fewer functional groups. The sorbent–solute H‐bonding interactions between the solute functional groups and the polymer C?O and NH functional groups are probed with attenuated total reflection infrared spectroscopy (ATR‐IR). The H‐bonding interactions of the polymer C?O and NH groups with the solutes result in changes in the IR amide band wavenumbers of ADMPC upon solute adsorption. The nanostructure of an ADMPC cavity and the potential interactions with the chiral solutes are proposed based on the sorbent–solute–solvent HPLC data, the sorbent–solute IR data, and the sorbent–solute molecular dynamics (MD) simulations. The results are consistent with the three point attachment hypothesis and indicate that a significant enantioresolution in ADMPC requires at least three different interaction sites for simultaneous H‐bonds and phenyl–phenyl interactions for phenylpropylamine (PPA) and various structurally similar chiral solutes. Chirality 2010. © 2009 Wiley‐Liss, Inc.     

血清GPAA1、SF、OPN与儿童急性淋巴细胞白血病危险度的关系及对血栓发生风险的评估效能研究

摘要 目的：分析血清糖基磷脂酰肌醇锚附着蛋白1（GPAA1）、铁蛋白（SF）、骨桥蛋白（OPN）与儿童急性淋巴细胞白血病危险度的关系及对血栓发生风险的评估效能。方法：选择我院自2017年1月至2022年12月接诊的112例急性淋巴细胞白血病患儿作为观察组，另选112例性别、年龄与观察组相匹配的健康体检儿童作为对照组。检测两组血清GPAA1、SF、OPN表达水平，分析不同危险度的急性淋巴细胞白血病患儿血清GPAA1、SF、OPN表达水平的差异性，观察急性淋巴细胞白血病患儿的血栓发生情况，通过受试者工作特征曲线（ROC）下面积（AUC）评价血清GPAA1、SF、OPN预测急性淋巴细胞白血病患儿发生血栓的效能。结果：观察组血清GPAA1、SF、OPN表达水平均高于对照组（P＜0.05）；在低危、中危和高危的急性淋巴细胞白血病患儿中，血清GPAA1、SF、OPN表达水平有差异（P＜0.05）；经Spearman相关性分析，血清GPAA1、SF、OPN表达水平与儿童急性淋巴细胞白血病危险度呈正相关（P＜0.05）；在112例急性淋巴细胞白血病患儿中，发生血栓12例，占10.71%；经多因素Logistic回归分析，血清GPAA1、SF、OPN均是急性淋巴细胞白血病患儿发生血栓的独立预测因素（P＜0.05）；经ROC曲线分析，血清GPAA1、SF联合OPN预测急性淋巴细胞白血病患儿发生血栓的AUC为0.901。结论：血清GPAA1、SF、OPN与儿童急性淋巴细胞白血病危险度密切相关，联合预测患儿发生血栓的效能较好，对此病的诊治具有重要指导意义。