The agrochemical arsenal versus the enemies of plants. General considerations

Plants are attacked, not only by various microorganisms, but also by other enemies, such as molluscs, nematods, mites, and insects. They have evolved complex and efficient mechanisms to defend themselves against pathogens (hypersensitive response, systemic acquired resistance) and herbivores (release of volatile compounds that attract predators of the herbivores, accumulation of proteinase inhibitors). Yet, the confrontation of the plants with their invaders can also turn to the advantage of the latter. In the past, the attacks of crops regularly brought about dramatic economic losses. From the World War II onwards, the development of organic chemistry associated with a growing awareness of the problems of agriculture has resulted in the production of a constantly growing number of plant protection products. They are currently divided into about ten classes, the herbicides, fungicides, and insecticides-acaricides making up more than 90% of the world market. Most of the agrochemical products put on the market over these last three decades are used in relatively low doses and have a more favourable toxicological and ecotoxicological profile than those of the former pesticides, many of which are now withdrawn from the market. Several more or less recent families are derivatives of metabolites from various organisms. Thus, the improvement achieved in the protection of crops is outstanding. However, one on the main side-effect is an environmental imbalance that has entailed a dependency on agrochemicals. Quite judiciously, alternative strategies (elicitors, genetic engineering, etc.) have been initiated or developed over the last decade.     

营养膜无土栽培技术

前言营养膜技术(Nutrient Film Technique简称NFT)是国外广泛采用的一种特殊的无土栽培方法。它是将植物栽植在一个狭长的不透水的营养槽中,槽中有缓慢流动的营养液。植物根系的一部分浸没在营养液中,一部分露在空气中,植物从这种小环境中吸收水、营养物和氧气。由于这种方法采用很薄一层营养液在根际周围流动,裸露的根     

The relative importance of prenatal and postnatal maternal influences on growth in mice

Summary The cross-nursing technique was used to assess the relative importance of prenatal and postnatal maternal influences on growth in mice from an unselected population originated from a cross of four highly inbred strains. Body weights were studied at birth, 7-, 14-, 21- and 42-days, in addition to the weight gains between these ages and tail length at 21 and 42 days of age. At littering, each dam in each nursing set retained two of her own offspring and two were transfereed to each of the other dams in the set, so that each nursed litter contained six young representing three mothers. Prenatal influences accounted for 37, 15, 10, 11 and 13 % of the total variation in the respective body weights, while postnatal influences accounted for 0, 64, 65, 49 and 14% at the respective ages. In the case of weight gains, prenatal influences were responsible for 16, 4, 6 and 30%, while postnatal influences were responsible for 66, 66, 31 and 7% of the total variation in gain during the respective four periods examined. Apparently the individual weight gain from 7 to 14 days was a better measure of the lactational performance of the dam than individual 14-day weight. For tail length, prenatal influences accounted for 6 % and 4 % of the total variation in tail length at 21 and 42 days, respectively, while postnatal influences accounted for 60 % and 24 % at the respective ages. Generally, there was no indication of an important interaction between the nurse and the nursed young at any stage studied.     

内含肽介导的蛋白连接技术及其应用

内含肽介导的蛋白质剪接是一种自发的翻译后事件,内含肽可介导其自身从前体蛋白上切除,同时将其两侧的外显肽连接起来.在过去10多年中,基于蛋白质剪接原理发展出的蛋白连接技术被广泛的用于蛋白质工程的研究中.这些技术打破了化学合成方法中对目标物大小的限制,有助于化学和生物学的研究.针对近年由蛋白质连接演化出来的新技术及其应用做简要的阐述.     

Une lame de faucille sous la stèle gravée Chalcolithique dite du « Chef de tribu », Vallée des Merveilles, région du Mont Bego, Tende, Alpes-Maritimes

The carved stele known as the “head of the tribe”, attributed to the Chalcolithic, erected at an altitude of 2290 m in the chaos of blocks in the Merveilles torrent in the Mont Bego region at Tende, was removed from its original standing place. Earth extracted from under the stele and sieved yielded a sickle blade in very fine and homogeneous Bedoulian pale biege translucid flint, pressure flaked on a heated core. The blade bears a light polish caused by cereal harvesting. This sickle blade is similar to those widely used in the southern Chassey culture (4300 to 3000 years before our era) but also sometimes in the Campaniform culture, during the ancient and middle Bronze age, like in Murée cave, in the Verdon gorges. The location of the sickle blade at the foot of the carved stele, known as the “head of the tribe”, is not just coincidental. It is highly probable that the blade was intentionally placed beside this rock. It is seemingly during a ritual ceremony that this sickle blade, probably still inserted in a wooden handle, was intentionally placed, in a propitious gesture or as an offering, beside the stele known as the “head of the tribe”.     

Das Präkambrium. Die Wiege des Lebens

The Precambrian is the cradle of life. With a time span of about 4 Billion years it represents the largest part of earth history. Life changed the planet during the Precambrian by a lot of interactions with plate tectonics and raised into better qualities. A special milestone was the release of free oxygen by the stromatolithes at about 2.5 Billion years. An extreme bottleneck for the evolution of life was the Snowball Earth representing the freezing of the entire earth surface and the covering by an ice sheet. Plate tectonic processes were responsible for the melting of the ice sheet. In the aftermath of that glaciation the rapid radiation of the first complex higher life forms begun. These were represented by the so‐called Ediacara Biota, which occurred in the time span of about 630 and 543 Million years before today. The Ediacara Biota are unique in the evolution of life and existed in a close interaction with a leather‐like biomat at the sea‐floor which provided stability, hide and food. Among the Ediacara Biota the first primitive arthropods, the molluscs and the anthozoans occurred. In addition, in the fossil record are reported a lot of mystic life forms without a good or any classification. The Ediacara Biota represent the critical evolutionary step to pave the way for the explosion‐like radiation of life during the Cambrian that started at 542 Million years before present.     

L’utilisation des reliefs pariétaux dans la réalisation des signes au Paléolithique supérieur

For a long time, the images of the Upper Paleolithic were represented in a way that emphasized their aesthetic qualities and ignored the specific characteristics of their natural supports. It is more damageable as the architecture of the decorated caves plays a real part, at different levels, in the elaboration of the parietal devices. As omnipresent elements of these devices, the signs play a determining part in this architecture. Analysing the links between the signs and their direct supports brings to light the various ways in which parietal devices can be used and also the integration and research for the volumes and frame. A study led inside the caves on a sample of 692 signs, distributed in the franco-cantabric paleolithic space, makes apparent the variety of the graphic choices left to the artists standing in front of the wall.     

Phylogenetic implications of the Protocrinoida: Blastozoans are not ancestral to crinoids

A traditional, widely cited hypothesis for over a century posits the origin of the crinoids from blastozoans. The blastozoan hypothesis is contradicted by the discovery of a new crinoid order, the Protocrinoida. Protocrinoids exhibit many traits that are consistent with a basal crinoid phylogenetic position, but inconsistent with a blastozoan ancestry. Protocrinoids are among the oldest crinoids and are therefore stratigraphically correctly placed. The blastozoan hypothesis in contrast, relies on putative homologies between blastozoans and crinoids taken from taxonomically and stratigraphically disparate representatives of both groups; these disparities indicate homoplasy rather than propinquity of descent. Data supporting these ideas are reviewed here. These findings reinforce insightful observations made by Georges Ubaghs decades ago with less data.     

The birth of the Acheulian techno-complex in the Caucasus region

The lithic industries of the sites Kermek, Ciscaucasia (2.1–2.0 Ma) and Karakhach, South Caucasus (1.85–1.78 Ma) contain almost all the components of the Acheulian, indicating that this techno-complex appeared in the different areas of the Caucasus region not later than at the end of the Gelasian. Such extremely old ages of these industries as well as a number of their features due to the influence of the local raw material (tabular clasts) suggest that they were formed independently of the Early Acheulian industries known in Africa and the Near East. The very early appearance and further dispersal of Early Acheulian in the Caucasus can be explained by the presence there of raw materials with qualities supporting the production of large tools inherent of Acheulian, and by the very favorable natural conditions of the region in the final Gelazian-initial Calabrian (low or medium altitude terrain with subtropical climate and savanna-like landscape).