La faune malacologique des calcaires éocènes de la région de Sabarat (Pyrénées ariégeoises)

Limestone beds included in the «Poudingue dePalassou around Sabarat (Ariège) contain a Gasteropod fauna known since J.-B. Noulet's works (1857). The systematic inventory of the different localities and the paleontological study of the material collected prove that two successive and clearly different Mollusc faunas existed. The bartonian fauna with Ischurostoma formosum minutum (Noulet) and Biomphalaria vasseuri (Roman) is preceded by a lower lutetian fauna with Biomphalaria pseudoammonius (Scholtheim): in the latter, two paleoecological groups are opposed according to the sheltered channels of two kinds in which limestones beds have been built. Besides, the chronostratigraphic consequences imply that the middle part of the «Poudingue de Palassou has been formed from Lower Lutetian to Bartonian.     

Plant Resources from the Bronze Age and the first Iron Age in the northwestern arc of the Mediterranean Basin

This paper updates the question of plant resources during the Bronze Age and First Iron Age in the northwestern Mediterranean Basin. Among the cereals, six-row hulled barley is dominant throughout the territory, whereas naked and hulled wheats take on greater or lesser roles from region to region. Millet cultivation developed during the Bronze Age and became widespread in the First Iron Age. Apart from cereals, pulses, oil species and fruit appear to be secondary. Results from the study of archaeobotanical remains on wetland sites, however, lead us to question this finding, as oil plants and fruits are much better represented in waterlogged conditions. The cultivation of vine began in the First Iron Age. In spite of a number of characteristics common to plants throughout the study area, regional differences, evident in the Bronze Age, seem to dissipate in the First Iron Age.     

Effect of “helper lipid” on lipoplex electrostatics

Lipoplexes, which are complexes between cationic liposomes (L⁺) and nucleic acids, are commonly used as a nucleic acid delivery system in vitro and in vivo. This study aimed to better characterize cationic liposome and lipoplex electrostatics, which seems to play a major role in the formation and the performance of lipoplexes in vitro and in vivo. We characterized lipoplexes based on two commonly used monocationic lipids, DOTAP and DMRIE, and one polycationic lipid, DOSPA—each with and without helper lipid (cholesterol or DOPE). Electrical surface potential (Ψ₀) and surface pH were determined using several surface pH-sensitive fluorophores attached either to a one-chain lipid (4-heptadecyl hydroxycoumarin (C17HC)) or to the primary amino group of the two-chain lipids (1,2-dioleyl-sn-glycero-3-phosphoethanolamine-N-carboxyfluorescein (CFPE) and 1,2-dioleyl-sn-glycero-3-phosphoethanolamine-N-7-hydroxycoumarin) (HC-DOPE). Zeta potentials of the DOTAP-based cationic liposomes and lipoplexes were compared with Ψ₀ determined using C17HC. The location and relatively low sensitivity of fluorescein to pH changes explains why CFPE is the least efficient in quantifying the differences between the various cationic liposomes and lipoplexes used in this study. The fact that, for all cationic liposomes studied, those containing DOPE as helper lipid have the least positive Ψ₀ indicates neutralization of the cationic charge by the negatively-charged phosphodiester of the DOPE. Zeta potential is much less positively charged than Ψ₀ determined by C17HC. The electrostatics affects size changes that occurred to the cationic liposomes upon lipoplex formation. The largest size increase (based on static light scattering measurements) for all formulations occurred at DNA⁻/L⁺ charge ratios 0.5-1. Comparing the use of the one-chain C17HC and the two-chain HC-DOPE for monitoring lipoplex electrostatics reveals that both are suitable, as long as there is no serum (or other lipidic assemblies) present in the medium; in the latter case, only the two-chain HC-DOPE gives reliable results. Increasing NaCl concentrations decrease surface potential. Neutralization by DNA is reduced in a NaCl-concentration-dependent manner.     

Differences in preterm and term milk fatty acid compositions may be caused by the different hormonal milieu of early parturition

Introduction

The hormonal milieus of pregnancy and lactation are driving forces of nutrient fluxes supporting infant growth and development. The decrease of insulin sensitivity with compensatory hyperinsulinemia with advancing gestation, causes adipose tissue lipolysis and hepatic de novo lipogenesis (DNL).

Subjects and methods

We compared fatty acid (FA) contents and FA-indices for enzyme activities between preterm (28–36 weeks) and term (37–42) milks, and between colostrum (2–5 days), transitional (6–15) and mature (16–56) milks. We interpreted FA differences between preterm and term milks, and their changes with lactation, in terms of the well known decrease of insulin sensitivity during gestation and its subsequent postpartum restoration, respectively.

Results

Compared with term colostrum, preterm colostrum contained higher indices of DNL in the breast (DNL-breast) and medium chain saturated-FA (MCSAFA), and lower DNL-liver and monounsaturated-FA (MUFA). Preterm milk also had higher docosahexaenoic acid (DHA) in colostrum and transitional milk and higher arachidonic acid (AA) in mature milk. Most preterm-term differences vanished with advancing lactation. In both preterm and term milks, DNL-breast and MCSAFA increased with advancing lactation, while DNL-liver, MUFA, long chain SAFA and AA decreased. DHA decreased in term milk. MUFA was inversely related to MCSAFA in all samples, correlated inversely with PUFA in colostrum and transitional milks, but positively in mature milk. MCSAFA correlated inversely with PUFA in mature milk.

Conclusion

Higher maternal insulin sensitivity at preterm birth may be the cause of lower MUFA (a proxy for DNL-liver) and higher MCSAFA (a proxy for DNL-breast) in preterm colostrum, compared with term colostrum. Restoring insulin sensitivity after delivery may be an important driving force for milk FA-changes in early lactation.     

人参内生细菌ge21菌株的鉴定及抑菌活性测定

从人参根内分离到一株细菌ge21,经形态特征观察、生理生化特性测定和16SrDNA序列分析,表明该菌株同已知菌Paenibacillus granivorans的相似性最高,为96.89%,初步认定为类芽孢杆菌属的一个潜在新种。抑菌试验结果表明,该菌株对尖孢镰刀菌(Fusarium oxysporium)、寄生疫霉菌(Phytophthora parasitica)、剑麻炭疽病菌(Colletotrichum agaves)、烟草赤星病菌(Alternaria longipes)、稻瘟病菌(Pyricularia oryzae)、人参立枯病菌(Rhizoctonia solani)、人参疫病菌(Phytophthora cactorum)和人参菌核病菌(Sclerotinia schinseng)均有一定的抑菌活性。     

从水稻细胞核中制备分子量达到Mb级的DNA

用水稻黄化苗作实验材料,经蔗糖不连续梯度纯化细胞核、琼脂糖包埋、蛋白酶消化释放DNA,脉冲交变电泳显示所得DNA样品分子量在200kb至3Mb之间,其中大量集中在2.2Mb处.所得DNA容易被多种内切酶消化和连接,可用于构建水稻YAC文库和大尺度物理图的研究.     

Nouvelles donnéessur les mollusques continentaux du Thanétien inférieur sous-pyrénéen. Interprétation stratigraphique et paléoécologique

Investigations carried out on the argillaceouslacustrine sedimentary rocks interbedded with marine lower Thanetian (lower Eocene) in the sub-pyrenean basin of southern France allowed the discovery of a micro-molluscan fauna: Carychium (Carychium) munieriBriart & Cornet, Carychium (Carychiopsis) cairocurbum nov. sp. and Valvata (Cincinna) indecisaCossmann. C. munieri and V. indecisa are known also from the upper Montian (early lower Eocene) of Belgium.Bivariant and multivariant analysis of several populations of C. munieri seem to document the presence of two morphotypes in the Montian of Belgium, only one persisted into the upper Thanetian in southern France.In the belgian Montian, these faunas appearedwhen climate was becoming warm.     

Proposition d’un référentiel taphonomique fossile de faunes issues d’avens-pièges

Pitfalls are formations characterized by a vertical opening that connects the karstic system to the outside. The presence of faunas trapped without the intervention of man or carnivores, offers the opportunity to establish a fossil referential of modifications generated by identified taphonomic agents. Three natural deposits containing large faunal accumulations feed this work. Their characteristics differ. The Igue des Rameaux, to Saint-Antonin-Noble-Val in Tarn-et-Garonne, is a pitfall which contains two accumulations of fauna independent from the Middle Pleistocene. Scavenging by man and carnivores (hyenas and wolves) are observed. The Igue du Gral, to Sauliac-sur-Célé in Lot, is a second pitfall. His principal phase of filling took place 14,000 years ago. Man did not exploit this assemblage. The activity of wolves is locally important, some animals are scavenged. The Grotte de l’Escale, in Bouches-du-Rhône, contains a very important filling of lower and middle Pleistocene. For the levels presented here, only a very weak presence of carnivores is attested. The thar (Hemitragus bonali) is the majority specie. We describe here the main forms of climato-edaphic modifications: fragmentation, dissolution, weathering and deposits observed on the osseous material. A differential analysis enables us to evaluate the variability of the situations according to the stratigraphic units and the different species. In a second time, we estimate the impact of the taphonomic agents on the differential conservation of bones and skeletal representations. Many phenomena are producing a significant correlation between anatomical representations and osseous densities. However, we find for all the species a certain homogeneity in the skeletal profiles where no precise element dominates. In a last part, we give two examples of the use of the taphonomic phenomena in the individualization of filling episodes within sometimes disrupted stratigraphies.