Chronostratigraphie de la fin de la derniere glaciation,a la lumiere des resultats de l'etude lithostratigraphique et palynologique du site de Maisieres-Canal (Belgique)

The upper part of the palaeoclimatic sequence of Maisières-Canal shows a succession of four mild episodes at thetransition between the Pleniglacial and the Late-Glacial. Those four mild fluctuations are respectively correlated with Langerie, Lascaux, Angles-sur-l'Anglin and Pré-Bölling oscillations.     

The genome of Zea mays,its organization and homology to related grasses

The pattern of genome organization of Zea mays has been analyzed, and the relationship of maize to possible progenitor species assessed by DNADNA hybridization. Reassociation of 470 and 1,350 bp fragments of maize DNA to various C₀t values demonstrates that the genome is composed of 3 major kinetic classes: highly repetitive, mid-repetitive, and unique. Mini-C₀t curves of the repetitive sequences at short fragment length indicate that the highly repetitive sequence class is 20% of the genome and is present at an average reiteration frequency of 800,000 copies; the mid-repetitive sequence class is 40% of the genome and is present at an average reiteration frequency of 1,000 copies. Thermal denaturation studies show that the highly repetitive sequences are 12% divergent and mid-repetitive sequences are 6% divergent. Most of the genome is organized in two interspersion patterns. One, approximately one-third of the genome, is composed of unique sequences of average length 2,100 bp interspersed with mid-repetitive sequences; the other, also one-third of the genome, is mid-repetitive sequences interspersed with highly repetitive sequences. The repetitive sequences are 500 to 1,000 bp by electron microscopic measurement. The remaining third of the genome is unique sequences farther than 5,000 bp from a palindromic or repetitive sequence. Hybridization of maize DNA from Midwestern Dent to popcorn and related grasses indicates that both the unique and repetitive sequence elements have diverged. Teosinte and popcorn are approximately equally divergent from Midwestern Dent whereas Tripsacum is much more divergent. The divergence times calculated from the depression of T_m in heterologous duplexes indicate that the divergence within Zea mays and between maize and near relatives is at least an order of magnitude greater than expected. This high degree of divergence may reflect the pressures of domestication of maize.     

Fluorescent reagents for the labeling of glycoconjugates in solution and on cell surfaces

Rhodamine and fluoresceine containing hydrazides were synthesized and used for fluorescent labeling of glycoconjugates on cell surface or in solution. The procedure involves the oxidation of the glycoconjugates with sodium metaperiodate or galactose oxidase to form an aldehyde group which reacts with the respective hydrazides. The method was applied for the modification of cell surface sialic acid and galactose residues on thymocytes and nematodes as well as for the labeling of glycoproteins and gangliosides in solution. The many possible application of these highly fluorescent compounds in the study of cell surface events is considered.     

Lambda transducing phages derived from a FinO- R100::lambda cointegrate plasmid: proteins encoded by the R100 replication/incompatibility region and the antibiotic resistance determinant.

Summary Three transducing phages have been isolated from pEDR20, an R100:: cointegrate plasmid in which the insertion inactivated the R100 finO gene. Physical analysis of the three phages showed that the is inserted at kilobase coordinate 81.3 of R100. All three phages carry different amounts of R100 DNA in the left arm of . Each phage contains IS1b, the mer genes and the region between coordinate 81.3 and 88.6; thus, all contain the genes necessary for R100 replication. One phage, VA73, contains the entire r-determinant of R100 in addition to the above DNA. Five proteins coded by the region between 81.3 and 88.6 were detected. These had subunit molecular weights of 10,400; 12,200; 16,200; 19,600; and 38,300. The first was made constitutively and the other four only from a promoter. Other constitutive proteins were one from the cml fus region with a molecular weight of 22,400 (cml) and two from the str sul region with molecular weights of 31,500 (str?) and 30,100 (sul?). Mercuric ion induced synthesis of at least 10 proteins. Six of these were known from earlier work. The total size of the proteins which appear to derive from the mer genes exceeds by a factor of 1.5, the coding capacity of this region without overlapping genes. Some, or all of these extra proteins may be chromosomal in origin, possibly derepressed in response to mercury gene products.     

Cell cycle analysis of tumour-derived cultures ofCrepis capillaris: A kinetic analogy with proliferation of animal tumour cells

Summary Analysis of the cell cycle by three methods has revealed unusual kinetics of proliferation in tumour derived suspensions ofCrepis capillaris. The different methods of analysis yield different estimates of cycle phase durations, and such discrepancies have been explained in terms of low growth fractions with rapid total cycle traverse. Specifically, confidence in the estimation of G₂ duration by the fraction of labelled mitosis analysis, and comparison with shorter G₂ estimates obtained by the two other methods, suggests that cells drop out in G₁. However, cells which do not drop out of the proliferative compartment traverse G₁ extremely rapidly. Extremely short cell cycle durations in which the G₁ phase is virtually non-existent are uncharacteristic of plant cell suspension cultures, in which the G₁ phase has previously been shown to be extended as compared with meristematic root tip cells. A model has been proposed in which a central core of rapidly dividing cells continuously loses cells into a subpopulation of resting or G₀ cells with the G₁ DNA content. Similarities between plant and animal tumours with respect to cell growth and division are discussed.     

Regional immunotherapy has a detrimental effect on the response to combined irradiation and chemotherapy in locally advanced non-small cell bronchogenic carcinoma

Summary Twenty-one patients with stage III M₀ non-oat cell bronchogenic carcinoma confined to the thorax were randomized to receive either intrapleural BCG (10⁷ cfu, Tice strain) or intrapleural saline 3 weeks prior to beginning combined irradiation and chemotherapy. Radiation to the primary tumor and regional nodes was given at a dose of 3,000 rad in ten sessions and was followed in 7–14 days by CAMP chemotherapy (cyclophosphamide, adriamycin, methotrexate, and procarbazine) for a planned duration of 6 months. Isoniazid, 300 mg/day, was given to all patients for 3 months starting 1 week after intrapleural therapy. There were no significant differences in pretreatment prognostic factors or in response to radiation therapy. The patients receiving intrapleural BCG in addition to radiation and chemotherapy had a median survival of 18 weeks, significantly shorter than that for the patients receiving intrapleural saline (54 weeks, P=0.017).Presented in part at the 16th Annual Meeting of the American Society of Clinical Oncology, San Diego, California, May 27, 1980     

Two cases of trisomy 21 and one XXY case with atypical clinical features

Summary Three patients with mental retardation and multiple congenital abnormalities are described.Although their clinical appearance was not suggestive of Down's syndrome, chromosome studies showed a non-disjunctional trisomy 21 in two of the patients. The third case had an unsuspected XXY karyotype.     

Mutations determining generalized resistance to aminoglycoside antibiotics in Escherichia coli.

Summary Mutations conferring resistance to low levels of kanamycin in Escherichia coli have been mapped at 3 locations: the unc locus (min. 83), a locus we have designated, kanA (min. 72), close to strA (rpsL), and a locus at min. 86.5 previously discovered by Plate (1976) that we have designated ecfB. The unc and ecfB mutations are associated with defects in energy metabolism, while mutations at kanA may be in the gene coding for ribosomal protein S12 (rpsL). The three types of mutations cause cross resistance to a number of different aminoglycoside antibiotics and the effects of the mutations are cumulative in combination.     

The hairpencils of the flour moth Ephestia kuehniella

The hairpencils of the Mediterranean flour moth, Ephestia kuehniella Zeller, are tufts of modified scales between the seventh and eighth abdominal segments of the adult males. The fine structure and development of a hairpencil organule is described. A process of the trichogen cell secretes the modified scale and then withdraws, and the cell invaginates forming a microvillous lumen into which pheromone is probably secreted. This lumen communicates with the outside via rows of pores in the hollow scale. The opening of these pores when the moth emerges from the pupal cuticle may be a result of the drying out of the membrane that covered them. The socket of the hairpencil scale is secreted by a tormogen cell.
The hairpencils of male Lepidoptera differ in position from family to family, but the organules that compose them seem to share a common structure. Epidermal glands and organules are classified in a scheme that takes account of their mode of development.