Anales de biología Vol. 10 (1986) Biología general, 2
Ir a Estadísticas
Permanent URI for this collection
Browse
Recent Submissions
- PublicationOpen AccessEstudio de la autodepuración microbiológica y fisico-quimica de aguas residuales por lagunaje profundo(Murcia: Universidad de Murcia, Servicio de Publicaciones, 1986) Berná Amorós, Luis Miguel; Torrella Mateu, Francisco; Soler, A.; Sáez, J.; Llorens, M.; Martínez, I.; Facultad de BiologíaA study of the chemical and microbiological self-depuration process of urban waste-waters in a deeppond stabilization system (15000 m3 ) is presented. The pond is localized in the Campus of the University of Murcia {Spain). The study covers two independent periods of waste-water stabilization: November 1984-July 1985 and September 1985-March 1986. The pond was completely emptied between the two periods. Among the various physiological parameters studied, the following are presented in this paper: temperature, dissolved 0 2 , alkalinity, pH, and BOD5 • Microbiological analysis included total and fecal coliforms, fecal streptococci, Clostridium perfringens, and coliphages, ali of them being water pollution indicators. In the geographical area where the lagoon is located (SE Spain), the self-depuration process is relatively fast in sulface waters (0-2 m). Periods of 30 to 50 days permit a significative decrease in the organic matter content (70% BOD,) and the microbial indicators (99.9'% total and fecal coliforms, 90% C. perfringens, 100% fecal streptococci, and 85% coliphages). Nevertheless, the selfdepuration process shows a diminished rate in the deep layers of the lagoon {under 2 m) because of the envíronmental conditíons prevailing in them: low temperature and oxygen. The latter aspect if magnified in periods of water stratification, when a pronounced anaerobiosis is generated under the thermocline and the temperature remains below 15 ºC. In the area where the self-depuration system has been studied, the reutilization of the waters of deep pond systems does not present chemical or mícrobiological risks for certain uses (e.g., irrigation), if sulface waters are used after an appropriate self-depuration period. The latter depending on the organic load and the thermal regime under which the system has evolved. Keywords: Wastewater. Self-depuration. M icrobiology. Physico-chemistry.
- PublicationOpen AccessPerfil isoenzimático de hexoquinasa y enolasa en tejidos neurales(Murcia: Universidad de Murcia, Servicio de Publicaciones, 1986) Delicado, E. G.; Torres, M.; Millaruelo, A.; Miras Portugal, M. T.; Facultad de BiologíaTissues derived from the neural crest showed a characteristic distribution and activity for each glycolitic isoenzyme. The hexokinase actívity in chromaffin tissue, pheochromocytoma and melanoma was associated with the particulate fraction of the homogenate as previously described for brain hexokínase. The experimental values obtained were 1, 2.1 and 1.68 U/g respectively, corresponding to type I isoenzyme (neural isoenzyme). In spite of the hexokinase, the enolase activity ín these tissues was found in the cytosolíc fraction. The activities were 13, 25 and 110 Ulg for chromaffin tissue, pheochromocytoma and melanoma, respectively, corresponding to the r,:y hybrid form. In melanoma sorne traces of the ctct form, a non neural isoenzyme, could be detected.
- PublicationOpen AccessAsimilación metabólica de los alcoholes en drosophzla: nutrición y detoxificación(Murcia: Universidad de Murcia, Servicio de Publicaciones, 1986) Atrian, S.; González Duarte, R.; Facultad de BiologíaAlcohol rnetabolism in Drosophila has recently attracted a lot of interest probably due to the essentiai role that the enzyme alcohol dehydrogenase plays in alcohol transforrnation. Species differ markedly in alcohol tolerance and this is attributed to ADH. While some species can cope with high ethanol concentrations (28%), others do not survive when reared in rninimal amounts (0'9%). Most of the species belong to an interrnediate group being able to tolerate and rnake use of alcohols produced in ferrnenting fruits which frequently constitute their natural habitats, al least during embryonic and larval developrnent. The analysis of ethanol metabolisrn and other primary alcohols, will help to establish not only the biochernical transformations, the enzyrnes involved and the relationships between other rnetabolic pathways but also to clarify the various factors relevant to the species adaptation towards alcohol-rich or rnoderately rich environrnents. Different types of evidence seern to indicate that one of these key factors is clearly ADH. In its absence, species become extremely sensitive to ethanol. Yet, it is still unclear which enzyrne features account ' for higher ethanol tolerance. Avalaible data suggest that the kinetic coeficient Vrnax and the quantity of enzyrne synthesized could be the rnost relevant factors in alcohol adaptation. On the other hand, kinetic and structurai studies of ADH reveal that ethanol utilization probably represents a recent evolutionary acquisition and was not associated initially with the enzyrne. Other enzyrnatic systerns help Drosophila in the exploitation of alcohol-rich environments, although they only account for sorne 10% of alcohol utilization. Aldehydes produced are further oxidized to carboxilic acids and this seems to be produced by an aldehyde dehydrogenase (ALDH), recently characterized in Drosophila, which shares relevant biochemical properties with liver ALDH. Ethanol is then eventually transforrned to acetic acid and acetylCoA which may serve as substrate for fatty acid synthesis or be oxidized in the Krebs cycle. All appears to be different when ADH acts on secondary alcohols. Highly toxic, rnetabolically inert compounds are produced which at the sarne time inactivate the enzyrne. Nevertheless, ADH shows lowest Km values with these substrates. sornething that cannot be easily explained, at least in biological terrns. It has been clairned that greater affínity could be due to the type of chernical interaction between the substrate and the active site of the enzyrne. Studies have also been carried out to know the effect of ethanol and 1 or sucrose in alcohol rnetabolisrn to approach the real situation that Drosophila encounters in natural habitats. It has been proved that ethanol and sucrose, together or individually, exert a positive regulation on ADH activity. It is not clear what produces this effect: increased levels of synthesis of the enzyme, lower turnover rate, re-activation of preexisting less active molecular forrns or if it is directly produced by these compounds or its metabolic interrnediates. The positive regulatory effect of ethanol and sucrose combined only appears if sucrose concentration does not reach a threshold level, when this is exceeded, a negative effect would be produced. When sucrose, at permisible amounts under the inhibitory effect, is supplernented to an ethanol diet, positive rnetabolic regulation is also observed in the activities of lipogenic enzyrnes together with an increase in the triacylglycerol content.Other type of data seem to strenghten the view that ADH role in alcohol transfonnation is not necessarily related to its possible function in intermediary metabolism. Among these are the facts that in the absence of ethanol ADH-negative mutarits differ from wild-type individuals in these metabolic pathways and that sucrose done can modulate ADH activity. In Drosophila, a clear picture of the relationships between catabolic and anabolic pathways has not yet emerged and this also applies to individual pathways. Alcohol metabolism is a clear example: it is not known how the activities of enzymes involved in this process are regulated and if this is acchieved through a direct or indirect effect. Until this stage is reached much of the meaning of the experimental results will be difficult to grasp. Obviously, there is a long way to go before there will be an amount of data comparabre toother organisms, as is the case of mammals, frequently investigated because they serve as model systems for humans.
- PublicationOpen AccessCOMPARATIVE NEUROBIOLOGY. P. J. Mil!. Ed. Edward Arnold, Contemporary Biology. Londres, 1982, NEUROBIOLOGÍA. Gordon M. Shepherd. Ed. Labor, Barcelona, 1985.: Reseña bibliográfica(Universidad de Murcia, Servicio de Publicaciones, 1986) Costa Ruiz, Jorge de; Facultad de Biología
- PublicationOpen AccessProteasas extracelulares de una cepa enterotoxigenica de Vibrio cholerae no 0:l(Murcia: Universidad de Murcia, Servicio de Publicaciones, 1986) Navarro, J. M.; Gacto Fernández, Mariano José; Facultad de BiologíaThe alkaline proteolytic system from a non-agglutinable strain of V. cholerae isolated from water has been analysed. Maximal levels of extracellular protease activity are produced during the stationary phase of growth. The proteolytic activity of the system shows a high stability and their synthesis appears to be partially repressed by glucose. The enzyme system is compossed of four distinct proteolytic enzymes as evidenced by SDS-polyacrylamide gel electrophoresis with copolymerized gelatin as substrate.