In mammals, ocular photoreceptors mediate an acute inhibition of pineal melatonin by light. The effect of rod and cone loss on this response was assessed by combining the rd mutation with a transgenic ablation of cones (cl) to produce mice lacking both photoreceptor classes. Despite the loss of all known retinal photoreceptors, rd/rd cl mice showed normal suppression of pineal melatonin in response to monochromatic light of wavelength 509 nanometers. These data indicate that mammals have additional ocular photoreceptors that they use in the regulation of temporal physiology.

Prochlorococcus marinus CCMP 1375, a ubiquitous and ecologically important marine prochlorophyte, was found to possess functional genes coding for the a and 1 subunits of a phycobiliprotein. The latter is similar to phycoerythrins (PE) from marine Synechococcus cyanobacteria and bind a phycourobilin-like pigment as the major chromophore. However, differences in the sequences of the ca and 13 chains compared with known PE subunits and the presence of a single bilin attachment site on the a subunit designate it as a novel PE type, which we propose naming PE-III. P. marinus is the sole prokaryotic organism known so far that contains chlorophylls a and b as well as phycobilins. These data strongly suggest that the common ancestor of prochlorophytes and the Synechococcus cyanobacteria contained phycobilins. Flow cytometric data from the tropical Pacific Ocean provide evidence that deep populations of Prochlorococcus possess low amounts of a PE-like pigment, which could serve either in light harvesting or nitrogen storage or both.

The physiological regulation of glutamine synthetase (GS; EC 6.3.1.2) in the axenic Prochlorococcus sp. strain PCC 9511 was studied. GS activity and antigen concentration were measured using the transferase and biosynthetic assays and the electroimmunoassay, respectively. GS activity decreased when cells were subjected to nitrogen starvation or cultured with oxidized nitrogen sources, which proved to be nonusable for Prochlorococcus growth. The GS activity in cultures subjected to long-term phosphorus starvation was lower than that in equivalent nitrogen-starved cultures. Azaserine, an inhibitor of glutamate synthase, provoked an increase in enzymatic activity, suggesting that glutamine is not involved in GS regulation. Darkness did not affect GS activity significantly, while the addition of diuron provoked GS inactivation. GS protein determination showed that azaserine induces an increase in the concentration of the enzyme. The unusual responses to darkness and nitrogen starvation could reflect adaptation mechanisms of Prochlorococcus for coping with a light-and nutrient-limited environment.Prochlorococcus is a marine photosynthetic prokaryote ubiquitous in most intertropical areas of the oceans and is responsible for a significant part of the global primary production (for a review, see reference 27). Its unusual photosynthetic apparatus (12,13,15,29) and wide genetic diversity have attracted increasing scientific interest in recent years. Its ability to tolerate a very wide light gradient has been linked to the cooccurrence in the field of two ecotypes with distinct irradiance optima for growth and photosynthesis (21,40). While many reports have described these features in detail, little is known about other important aspects of Prochlorococcus metabolism, such as nutrient assimilation. In particular, the nitrogen assimilatory pathways in Prochlorococcus have not yet been studied. However, it is widely accepted that nitrogen is the main limiting nutrient in the upper layer of the oceans (27), and an understanding of the mechanisms involved in nitrogen assimilation could thus provide some keys to unveiling the remarkable ability of Prochlorococcus to colonize very oligotrophic regions. Nevertheless, such studies with Prochlorococcus face two problems: first, this organism is not easy to cultivate, and second, most isolated strains or clones contain contaminant heterotrophic bacteria. Only very recently, Rippka and coworkers described the first axenic strain, PCC 9511 (31), a typical high-light-adapted Prochlorococcus ecotype, allowing proper study of nonphotosynthetic metabolic pathways.In the present work, we have studied the physiological response of glutamine synthetase (GS) in cultures of Prochlorococcus subjected to different conditions by measuring transferase and biosynthetic activities and antigen concentration. The standard nitrogen assimilatory pathway in non-nitrogenfixing cyanobacteria is composed of a complex, highly modulated system of transporters, enzymes, and regulatory proteins (6). It allows...

Son escasos los estudios que analizan la relación entre conducta agresiva e inteligencia emocional. Este estudio examina la relación entre inteligencia emocional rasgo y los componentes motor (agresividad física y agresividad verbal), cognitivo (hostilidad) y afectivo/emocional (ira) de la conducta agresiva. El Trait Emotional Intelligence Questionnaire-Adolescents Short Form (TEIQue-ASF) y el Aggression Questionnaire Short version (AQ-S) fueron administrados a una muestra de 314 adolescentes (52.5% chicos) de 12 a 17 años. Los resultados indicaron que los adolescentes con altas puntuaciones en conducta agresiva física, verbal, hostilidad e ira presentaron puntuaciones significativamente más bajas en inteligencia emocional rasgo que sus iguales con puntuaciones bajas en conducta agresiva física, verbal, hostilidad e ira. Este patrón de resultados fue el mismo tanto para la muestra total como para chicos, chicas y los grupos de edad de 12-14 años y 15-17 años. Además, en la mayoría de los casos se hallaron tamaños del efecto grandes apoyando la relevancia empírica de estas diferencias.

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