A method to measure redox potential (Eh) and pH in agar media and plants shows that fungal growth is affected by and affects pH and Eh

The specificities of the plant environment and its effects on fungal growth are not yet fully explored. Both pH and Eh play a key role during this interaction, but are often studied independently or at different scales. We aimed at investigating whether the methods developed for the joint characterization of the pH and Eh in soil could be transposed to fungi. On artificial media, the growth of all 16 species tested significantly altered either Eh, pH or both. Measuring Eh reveals that even the species not modifying pH can have an impact on the surrounding environment. Reciprocally, fungi responded to pH and Eh parameters, both quantitatively with a decrease in colony diameter and qualitatively with colony aspect repeatedly and thoroughly modified. In infected oilseed rape plant stems, pH and Eh were significantly altered. The observed alcalinisation or acidification correlates with canker length. The joint characterization of both parameters will allow understanding the impact of fungi on their environment, and conversely of the environment on fungal growth. The availability of methods for measurement opens the prospect to study combinations of stresses, and get an understanding of the involvement of pH and Eh modifications in these interactions.     

着床期小鼠子宫内膜Le~y糖蛋白的动态变化

为了解子宫内膜Ｌｅ~ｙ糖蛋白在胚泡着床期间的变化,以及与胚泡表面阶段特异性Ｌｅ~ｙ抗原出现的关系,应用对Ｌｅ~ｙ寡糖特异的ＡＨ－６单抗为探针,通过ＳＤＳ－ＰＡＧＥ和Ｗｅｓｔｅｒｎｂｌｏｔ免疫酶标染色,观察了小鼠子宫内膜Ｌｅ~ｙ糖蛋白在着床期的动态变化和分布特点。结果表明：（１）未孕及着床前后的小鼠子宫内膜均含Ｌｅ~ｙ糖蛋白Ｍｒ５０～２００ｋＤ）,未孕内膜的含量明显高于着床期间的样品;（２）在着床日（Ｄ４）样品可见微量１６ｋＤ的Ｌｅ~ｙ糖蛋白条带;（３）未孕至Ｄ４的子宫内膜均有Ｌｅ~ｙ糖蛋白分泌至宫腔,但呈渐减趋势,未孕样品Ｌｅ~ｙ糖蛋白主要为分泌型,而Ｄ４样品Ｌｅ~ｙ糖蛋白主要存在于子宫内膜,宫腔液含量很少;结果提示子宫内膜Ｌｅ~ｙ糖蛋白在着床期间具有含量、组成和分布上的动态变化,这些变化可能与胚泡着床以及胚泡在宫腔内其表面Ｌｅ~ｙ糖抗原转为阳性密切有关。     

Specificity of DC-SIGN for mannose- and fucose-containing glycans

The dendritic cell specific C-type lectin dendritic cell specific ICAM-3 grabbing non-integrin (DC-SIGN) binds to "self" glycan ligands found on human cells and to "foreign" glycans of bacterial or parasitic pathogens. Here, we investigated the binding properties of DC-SIGN to a large array of potential ligands in a glycan array format. Our data indicate that DC-SIGN binds with K(d)<2muM to a neoglycoconjugate in which Galbeta1-4(Fucalpha1-3)GlcNAc (Le(x)) trisaccharides are expressed multivalently. A lower selective binding was observed to oligomannose-type N-glycans, diantennary N-glycans expressing Le(x) and GalNAcbeta1-4(Fucalpha1-3)GlcNAc (LacdiNAc-fucose), whereas no binding was observed to N-glycans expressing core-fucose linked either alpha1-6 or alpha1-3 to the Asn-linked GlcNAc of N-glycans. These results demonstrate that DC-SIGN is selective in its recognition of specific types of fucosylated glycans and subsets of oligomannose- and complex-type N-glycans.     

Les sclérobiontes des huîtres du Cénomanien supérieur du Mans (Sarthe,France)

Oysters of the Marnes à Pycnodonte biauriculata Formation, Upper Cenomanian (Guerangeri biozone) were significantly sampled in building works within the town of Le Mans (Sarthe, France). They are colonized by episkeletobionts (encrusting organisms) and endoskeletobionts (boring and bioeroding organisms). First ones include bivalves, polychaetes, foraminiferans and bryozoans. Second ones are represented by about fifteen ichnotaxa, the producers of which, when they are known, belong to ten taxa. The oysters, some of which have a large fixation surface, are allochtonous or at least parautochtonous. The settlement of sclerobionts began when the oysters were alive (Entobia isp.) and continued post-mortem on isolated valves, transported in their final depositional environment (Gnathichnus pentax). The significance of the coexistence of both Entobia and Gnathichnus ichnocoenosis is discussed.     

Extended Holstein small polaron model for charge transfer in dry DNA

In this paper, the charge transfer problem in dry DNA was investigated by employing an extended Holstein small polaron model with external potential traps being involved in consideration. The ground state energy and the probability amplitude of polaron in various DNA chains with different external trap potentials were obtained by variational method with the trial function being taken in coherent state form. The stability of transfered charges in various circumstances was discussed accordingly.     

Paranthodon africanus (broom) a stegosaurian dinosaur from the Lower Cretaceous of South Africa

The holotype of Paranthodon africanus (Broom) from the Kirkwood Formation (Lower Cretaceous) of the Algoa Basin, Cape Province, South Africa consists of a partial skull, the bones of which are very similar to those of Stegosaurus. Both sides of the maxillary tooth crowns have a bulbous cingulum and a very prominent central vertical ridge above the large apical denticle that is bordered anteriorly and posteriorly by four to seven smaller denticles. Diagnostically stegosaurian material is also known from the Lower Cretaceous of England (Craterosaurus) and China (Wuerhosaurus) and the Upper Cretaceous of India (Dravidosaurus).     

New data on Late Pleistocene small vertebrates from northern France

Quaternary small vertebrate assemblages from northern France, and more generally from northwestern Europe, are poorly recognized, and studied less than those from more southern, Mediterranean areas. However, important sites of human occupation are often found in these northern areas, with significant issues related to the occupation of these sites by Neanderthals and previous humans, as well as faunal dynamics under climatic pressure. In this paper, we present preliminary results from the study of small vertebrate assemblages from two Late Pleistocene sites of northern France: Mutzig (Alsace) and Le Rozel (Normandy). Both are ancient rock-shelters that have been excavated recently and have yielded evidence of Neanderthal occupation, but in very different contexts: Le Rozel is located in a coastal area of northwestern France contemporaneous with a temperate period, while Mutzig is located at the foot of the Vosges mountains in northeastern France and was occupied during a cold period. Consequently, even if these two sites are chronologically close to each other, differences in faunal composition are observed and discussed in relation to the geographic, climatic and biochronological context, in comparing the results from small vertebrates with those from other disciplines (numerical dating, large mammals).     

应用Le Bissonnais 法研究黄土丘陵区植被类型对土壤团聚体稳定性的影响

植被类型直接影响土壤特性,对土壤团聚体的形成和稳定性有重要影响,水稳性团聚体是反映黄土高原土壤抗蚀性的最佳指标。本文选择黄土丘陵区延河流域作为研究区域,应用Le Bissonnais(LB)法和Yoder法测定了森林、森林草原两种植被类型下土壤水稳性团聚体稳定性,对比分析了LB法3种处理的结果,并计算土壤团聚体平均重量直径（MWD）和可蚀性因子K值。结果表明：在LB法3种湿润处理下,预湿后扰动处理（WS）对土壤团聚体结构的破坏程度最大,处理后土壤水稳性团聚体以<0.2 mm为主;快速湿润处理（FW）对团聚体的破坏程度次之;慢速湿润处理(SW)对团聚体的破坏程度最小,处理后土壤水稳性团聚体主要以>2 mm团聚体为主;说明黄土丘陵区延河流域土壤团聚体破坏的主要机制是气爆作用（消散作用）和机械扰动。LB法的3种处理结果中预湿后扰动的测定结果与传统的湿筛法（Yoder法）更接近。LB法包含Yoder法的基本原理,能够全面、准确的测定土壤团聚体结构,适宜作为黄土丘陵区土壤团聚体测定方法。森林植被类型的土壤团聚体平均重量直径（MWD）大于森林草原植被类型,而且SW>FW>WS,但可蚀性因子K值却是森林植被类型小于森林草原植被类型。土壤水稳性团聚体由小颗粒向大颗粒转变,土壤结构趋于稳定。不同植被类型下土壤有机质含量不同,土壤团聚体形成过程及土壤团聚度也有差异,因而造成土壤可蚀性和土壤抗蚀性能不同。