The geographical and chronological pattern of herpetofaunal Pleistocene extinctions on the Iberian Peninsula

Despite the postulation of the “herpetofaunal stability hypothesis”, which suggests that the herpetofauna underwent relatively few changes during the Pleistocene, the amphibian and squamate faunas of western Europe are known to have progressively diminished during the Pliocene and the beginning of the Pleistocene. Iberian Early Pleistocene sites continue to document the presence of “exotic” herpetofaunal elements that are supposed to have disappeared from the mainland, such as Oriental vipers, agamid lizards, the anguids Pseudopus and Dopasia, and a representative of the green toad group (Bufo viridis sensu lato), as well as possibly gekkonids, a scincid lizard (Lygosominae), the anguid Ragesaurus and blind snake (Scolecophidia). The geographical and temporal pattern of these progressive southward withdrawals and extirpations on the Iberian Peninsula shows that extirpation events occurred in northern Spain at roughly the Olduvai paleomagnetic event and in southern Spain just before the Jaramillo paleomagnetic reversal, thus permitting us to establish a framework that can be used to complement the biochronological zonation of the Iberian Early Pleistocene.     

Arkaïm-Sintachta : expérience de la mise en valeur des steppes eurasiatiques à l’Âge du Bronze

The “Earth of fortified settlement” is one of the last big discoveries of the end of the XXth century. Situated on the oriental slopes of the mounts of Ural, fortified settlement, date the Middle Bronze Age. These strengthened structures are particular in the archaeology of steppes. They were built according to geometrical plans, Cities in oval being the most ancient, the rectangular cities being the most recent. The most remarkable are together of strengthened structures appropriate for the culture of Sintachta-Arkaïm. This city distinguishes itself from the others by the unique integrity of the works of fortification and by the graves which are connected to these last ones. Situated on a prominence, Arkaim consists of two defensive walls, maybe of a third, the rampart and the ditch. The space between the defensive walls was occupied by the houses of shape trapezoidale and directed as beams to the center of the city. The center of the city, the rectangular shape, was not built and formed a place where foyers were found. Complex entrances were at the four corner of the city. The excavations of fortified settlement and graves allowed to have an idea on the level of development of the everyday life at the time of the Middle Bronze Age in transouraliennes plains.     

La phalange distale du pouce d’Orrorin tugenensis (Miocène supérieur du Kenya)

The lion's share of articles dealing with the thumb anatomy of Plio-Pleistocene hominids has focussed on the capacity to manipulate and manufacture tools, and has largely neglected the locomotor aspects. However, in these hominids, the forelimb was still employed in locomotion. Certain of the anatomical characters classically associated with manipulation and/or fabrication of tools are already present in the Late Miocene species Orrorin tugenensis as shown by the terminal thumb phalanx BAR 1901'01. This specimen reveals crucial information suggesting that thumb morphology is not exclusively related to such tool using and manufacturing activities but reflects in a frequently bipedal creature a deeper adaptation concerning the precision grip essential for climbing and balancing, different from that of apes.     

The paleobiology of two adult skeletons from Baousso da Torre (Bausu da Ture) (Liguria,Italy): Implications for Gravettian lifestyle

This article presents the main skeletal characteristics of the two largely unpublished Gravettian adult skeletons from Baousso da Torre (Liguria, Italy). BT1 and BT2 were two adult tall males, who died aged respectively between 20 and 50 years, and between 20 and 30 years. Their body proportions fall within the range of variation known for the middle Upper Paleolithic, and their skeletal remains are characterized by considerable osteometric values, which fall consistently in the upper part of the Upper Paleolithic male sample variation. They show a high degree of upper limb lateralization, implying that they were likely involved in strenuous and/or repetitive unimanual tasks. They also exhibit very robust lower limbs, likely related to repeated long-distance travels in mountainous terrains. These results are in total agreement with previous hypotheses on Late Pleistocene population behavioral patterns.     

Recent aspects of genetic manipulation in Bacillus thuringiensis

The conjugative plasmid pAM beta 1 was transferred from Streptococcus faecalis to several strains of Bacillus thuringiensis by a filter-mating process. From a transconjugant clone of B. thuringiensis a hybrid plasmid resulting from an in vivo insertion into pAM beta 1 of a 3 Md DNA sequence was isolated. This 3 Md DNA molecule (Th sequence) is related to several host plasmids found in different serotypes of B. thuringiensis. A reciprocal conjugation-like process involving the transfer of pAM beta 1 from B. thuringiensis to S. faecalis was also demonstrated. The comparison of the restriction maps of the crystal genes from plasmid and chromosomal origins of different serotypes, six of which having been cloned in E. coli, revealed the existence of two classes of genes which are very similar in the map corresponding to the N-terminal part of the protein, and which differ essentially in the 3' region. The presence of the transposon-like Th sequence was found in several cases associated with the crystal gene in the same host plasmid, and a model for their structural organization is proposed.     

The interferon-induced enzyme 2-5A synthetase adenylates tRNA

The interferon-induced enzyme 2-5A synthetase is shown to adenylate tRNA. Yeast tRNAPhe was incubated with the enzyme in the presence of double stranded RNA (in this case polyI-polyC) and ATP or deoxyATP. The reaction products were analyzed by ribonuclease T1 digestion of the tRNA, polyacrylamide gel electrophoresis and autoradiography. Using ATP, the 2-5A synthetase adds one, two or three AMP residues to the 3'-end of the tRNA whereas when dATP is replacing ATP, only one nucleotide unit is added. It is concluded that one of the mechanisms of the interferon-induced antiviral effect may be an inhibition of the translation process caused by an inactivation of tRNA molecules by a 2-5A synthetase catalyzed 2'-adenylation of the 3'-end.     

Helical stereochemistry and chiral apple halves. 2. La coupe du roi via double helical complexation using oligo(bipyridine) strands and Cu(I)/Ag(I)

Oligo(bipyridine) strands and Cu(I)/Ag(I) form duplexes having a 2₁-screw coincidental with a C₂-axis. A segment containing a complete turn of the duplex can be considered to be a coupe du roi ensemble of two homochiral strands. Moreover, for D_2d symmetry monocationic Cu(I) complexes of bipyridine trimers and pentamers, addition of the requisite Cu(I) cations is a true chemical example of la coupe du roi. In this reaction, an achiral monocationic complex is converted into a multiple-cationic duplex of two homochiral and homotopic 2₁-helical halves. The chirality of the resulting duplex is a function of the particular set of bipyridine enantiotopic faces which are used for binding the additional cations. © 1993 Wiley-Liss, Inc.     

Isolation and characterization of faithful and altered clones of the genomes of cauliflower mosaic virus isolates Cabb B-JI, CM4-184, and Bari I

Full-length genomes of cauliflower mosaic virus (CaMV) isolates Cabb B-JI, CM4-184, and Bari I have been cloned in the SalGI site of plasmid pAT 153. The cloned DNAs were characterized by restriction mapping and infectivity assays. All the sites present in the virion DNAs were found in the cloned DNAs. Comparison of restriction maps with those of DNA from two other isolates which have been recently completely sequenced revealed a close relationship among the different isolates. Some of the clones appear to be faithful copies of the viral genomes and these viral inserts are infectious when inoculated into turnip plants. Various clones with deletions in the CaMV DNA have been isolated and characterized. Some of them may correspond to deletions naturally occurring in a subpopulation of the virus whereas others occurred during cloning. None of the deleted fragments are infectious when inoculated into plants. Strikingly, all the deletions overlap one or two of the specific single-stranded breaks characteristic of caulimoviruses, suggesting that sequences surrounding the breaks are not dispensable.