Searching by visual and acoustic cues among bushcrickets (Orthoptera: Tettigoniidae): will females remain faithful to a male who stops calling?

Abstract. Female nocturnal bushcrickets ( Requena verticalis: Listroscelidinae: Tettigoniidae: Orthoptera) orientate towards and approach a conspecific male by tracking the direction of its call. If a male stops calling during this approach, the female may remain faithful and continue on the same track or change direction and pursue another calling male. Factors that might influence this decision were examined experimentally. When presented with a male call in conjunction with a visual cue, females maintained orientation towards the visual cue following cessation of the call. Furthermore, when a visual cue was presented with an acoustic cue, females were more likely to be faithful, regardless of call intensity.     

Cloning and expression of an anti-LDL(-) single-chain variable fragment,and its inhibitory effect on experimental atherosclerosis

The in vivo modified forms of low-density lipoprotein (LDL) are important for the formation of foam cells and as mediators of the immuno-inflammatory process involved in the progression of atherosclerosis. Electronegative LDL, LDL(-), is a LDL subfraction with pro-inflammatory properties that is present in human blood. To investigate possible atheroprotective effects, an anti-LDL(-) single-chain variable fragment (scFv) was expressed in the methylotrophic yeast Pichia pastoris and its activity was evaluated in vitro against macrophages and in experimental atherosclerosis in Ldlr^-/- mice. The recombinant 2C7 scFv was produced in a yield of 9.5 mg of protein/L. The specificity and affinity of purified 2C7 scFv against LDL(-) was confirmed by ELISA. To assess the activity of 2C7 scFv on foam cell formation, RAW 264.7 macrophages were exposed to LDL(-) in the presence or absence of 2C7 scFv. The 2C7 scFv inhibited the uptake of LDL(-) by macrophages in a dose-dependent manner, and internalization of LDL(-) by these cells was found to be mediated by the CD36 and CD14 receptor. In addition, compared with untreated cells, lipid accumulation in macrophages was decreased, and the expression of Cd36, Tlr-4 and Cox-2 was downregulated in macrophages treated with 2C7 scFv. Importantly, compared with untreated mice, the treatment of Ldlr^-/- mice with 2C7 scFv decreased the atherosclerotic lesion area at the aortic sinus. In conclusion, our data show that 2C7 scFv inhibits foam cell formation and atherosclerotic plaque development by modulating the expression of genes relevant to atherogenesis. These results encourage further use of this antibody fragment in the development of new therapeutic strategies that neutralize the pro-atherogenic effects of LDL(-).     

Mathematical description of the interactions between cellular inactivating agents

A mathematical technique for characterizing the interactive effects that may occur when cells are treated with two or more toxic agents is developed. This technique is used to account for the previously unexplained properties of the dose-response relations for the uv-X-ray interaction in Escherichia coli B/r.     

Storm deposits in the Jurassic of the Moroccan High Atlas

Certain carbonate deposits in the Upper Jurassic succession of the western High Atlas mountains of Morocco are interpreted as having resulted from periodic storms operating on very shallow marine or supratidal sediments. Such storm deposits or “tempestites” are thought to be much more common than is usually recognized, and in certain climatic situations they are likely to be the rule rather than the exception.     

Brachiopod ecology in mid-Palaezoic sediments near Khenifra,Morocco

The modes of occurrence of a Silurian atrypid and a Devonian rhynchonellid near Khenifra in central Morocco are described. They are both thought to have lived on isolated shoals within muddy basins. A substrate for brachiopod attachment in each case was provided by lime-secreting algae. Most of the Devonian rhynchonellids are preserved in olistostromes, within Carboniferous shales, but some are in situ. The rhynchonellid, which is identified as Eoperegrinella, is thought to have taken over the ecological niche previously occupied by the atrypid, identified as Dubaria, during Devonian times. Descendent rhynchonellids of the same group in the Mesozoic lived in a similar way.     

Pattern of the evolution of HIV-1 enν gene in C?te d?Ivoire

Cête d׳Ivoire continues to have the highest HIV-1 prevalence rate in West Africa, although the infection number is in constant decline. The external envelope protein of the viruses is a likely site of selection, and responsible for receptor binding and entry into host cells, and therefore constitutes an ideal region with which to investigate the evolutionary processes acting on HIV-1. In this study, we analyse 189 envelope glycoprotein V3 loop region sequences of viruse isolates from 1995 to 2009, from HIV-1 untreated patients living in Cête d׳Ivoire, to decipher the temporal relationship between disease diversity, divergence and selection. Our analyses show that the nonsynonymous and synonymous ratio (dN/dS) was lower than 1 for viral populations analysed within 15 years, which showed the sequences did not undergo adequate immune pressure. The phylogenetic tree of the sequences analysed demonstrated distinctly long internal branches and short external branches, suggesting that only a small number of viruses infected the new host cell at each transmission. In addition to identifying sites under purifying selection, we also identified neutral sites that can cause false positive inference of selection. These sites presented form a resource for future studies of selection pressures acting on HIV-1 enν gene in Cête d׳Ivoire and other West African countries.     

Regulation of prostaglandin production and ectoenzyme activities in cultured aortic endothelial cells

Prostaglandin production, angiotensin-converting enzyme, and 5'-nucleotidase were measured in porcine aortic endothelial cells in situ (with a multi-well template on an opened aorta), in primary culture and in subcultures. Changes during culture were monitored and the effects of culture conditions were investigated by growing cells on a biological matrix or on plastic, by adding different sera to the growth medium, and by harvesting cells enzymically or mechanically. Prostacyclin production by endothelium in primary culture is highest immediately after cell isolation and subsequently declines; this pattern is repeated each time the cells are subcultured. The level at which production stabilises is approximately 200 pg X 10(6) cells-1 X h-1. Detaching cells by physical means stimulates production much more than enzymic dispersion; the type of serum or the presence of a biological matrix does not alter prostaglandin production. The relative amount of prostaglandin E produced increases with time, from approximately 20% of the prostacyclin production shortly after isolation to greater than 100% in subcultured cells. None of the culture conditions that we tested altered this trend. Angiotensin-converting enzyme activity decreases during primary culture, but activity can be sustained by including homologous serum (from whole blood or from platelet-free plasma) in the culture medium. The method of harvesting cells, or the presence of a matrix, did not affect enzyme activity. 5'-Nucleotidase also declines during culture, with a progressive decrease in both Km and Vmax from template to primary culture to subcultures. None of the variations in culture conditions prevented this change. Ecto-adenosine-deaminase activity, not detectable in cultured cells, can be measured in the template. Part of this activity was released by the vascular wall and could be due to plasma diffusing from the interstitial space.